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Estrogen plus androgen induced mounting in adult female hamsters
HORMONES AND BEHAVIOR 5, 227-234 (1974)
Estrogen Plus Androgen Induced Mounting in Adult Female Hamsters RALPH NOBLE Wisconsin Regional Primate Research Center, Madison, Wisconsin 53 706
This study demonstrated that the combined administration of estrogens and androgens activates the display of mounting by female hamsters. Forty-nine ovariectomized hamsters were injected daily with either estradiol (DHTP, N = 7); benzoatc (EB, N = 8); dihydrotestosterone propionate testosterone propionate (TP, N = 6); androstenedione (AD, N = 9); EB plus DHTP (N = 10); or estrone plus DHTP (El + DHTP, N = 9). All androgens
were administered at a dose of 1 mg per day for the fist 24 days and at a dose of 2 mg per day for the last 14 days. The EB dose was 6pg per day and the El dose was 100 rg per day. Females were tested for male behavior once a week starting on Day 10 of injections and for female behavior on Day 39. One hundred percent of EB + DHTP treated females; 67% of the El + DHTP treated females; 55% of the AD treated females; 33% of the TP treated females; 29% of the DHTF’ treated females; and none of the EB treated females mounted during at least one test. Only one of the E, + DHTP treated females showed the intromission pattern; otherwise most females which mounted displayed the intromission pattern. The median number of days preceding the onset of mounting ranged from 21 to 31 days and did not differ among treatment groups.
Females of many mammalian species mount, and the display of mounting is facilitated by androgen administration (Young, 1961; Beach, 196s). The extent to which androgen-dependent mounting is sexually dimorphic varies across species (Coy and Goldfoot, 1973). Few female hamsters mount, and female hamsters do not respond to androgen treatment regimens which fully reinstate mounting by castrate males (Tiefer, 1970; Swanson and Cxossley, 1971; Carter, Clemens, and Hoekema, 1972). Following chronic treatment with testosterone propionate, female guinea pigs mount with a frequency approximately one-fourth the frequency displayed by comparably treated males (Phoenix, Coy, Gerall, and Young, 1959; Diamond, 1965). In the female rat, treatment with testosterone propionate results in a frequency of mounting
approximately
one-half
the 227
Copyright 0 1974 by Academic Press, Inc. All rights of reproduction in any form reserved.
frequency
displayed
by comparably
228
RALPH NOBLE
treated males (Pfaff, 1970). Male and female mice display equally high rates of mounting following administration of testosterone propionate (Edwards and Burge, 1971a). The effectiveness of other hormone regimens in facilitating mounting by females is also species dependent. Estradiol benzoate is as effective as testosterone propionate in the female rat (Pfaff, 1970), and the male mouse (Edwards and Burge, 1971b), but is totally ineffective in the female mouse (Edwards and Burge, 1971b). Female guinea pigs in either natural or induced estrus occasionally mount as much as intact males (Beach, 1968); however, chronic administration of estradiol benzoate alone does not facilitate mounting in female guinea pigs (Antliff and Young, 1956). The present study examined the possibility that the combined administration of estrogen and dihydrotestosterone facilitates the display of mounting by female hamsters. Estradiol and dihydrotestosterone interact synergistically to restore the copulatory behavior of castrate male rats (Larsson, Sodersten, and Beyer, 1973; Baum and Vreeburg, 1973).
METHODS Subjects and housing conditions. Forty-nine females were purchased from Engle’s Hamster Farm (Farmersburg, Indiana) when approximately 2 mo of age (91-100gm body weight). The females were ovariectomized using pentobarbital anaesthesia (Nembutal, 100 mg per 100 gm body weight) two weeks before the start of hormone treatments. Females were housed in translucent plastic cages (38 X 33 X 17 cm), 3-5 per cage, on a reversed light cycle (L:D, 14: 10) with the lights off from noon to 10:00 PM. Purina Rat Chow and tap water were continuously available and the corn cob bedding (Sanicel, deodor grade) was changed weekly. Design and procedure. 1 Each female was assigned to one of six groups with all the females in a cage assigned to the same group. Group 1 received daily injections of 6pg estradiol benzoate (EB, N = 8): Group 2 received dihydrotestosterone propionate (DHTP, N = 7); Group 3 received testosterone propionate (TP, N = 6); Group 4 received androstenedione (AD, N = 9): Group 5 received 6 pg EB per day plus DHTP (EB + DHTP. N = 10); and Group 6 received estrone, IOOng per day, and DHTP (Er + DHTP, N = 9). All hormones were injected subcutaneously in 0.1 ml corn oil. The androgen lThe hormones used in the present study were obtained from the following suppliers: Testosterone propionate (4-androsten-17p-al-3ane propionate), Schering Corporation; Androstenedione (A’androsten-3.17-dione). Sigma Chemical Company: Dihydrotestosterone propionate (Sa-androstan-17pol-3une propionate), Steraloids. Incorporated; Estradiol benzoate (estratrien-3.1 ‘IO-diol 3-benzoate). Steraloids. incorporated; Estrone (A’ ,3*5 (I 6)+stratrien-301-l ‘l-one). Sigma Chemical Company.
FEMALE MOUNTING
229
dose was 1 mg per day for 24 days, followed by daily injections of 2 mg per day from Day 25 to Day 38. Females were tested for male behavior once a week starting ten days after the first injection. The day after the last test for male behavior, females were tested for the display of lordosis. Then three females from each group were sacrificed using an overdose of sodium pentobarbital and the glandes clitoris removed using a dissecting microscope and weighed (wet weight) to the nearest milligram using a Mettler H20 balance. At the end of the experiment, the flank glands of all females were measured using the procedure described by Vandenbergh (1973) to determine the longest diameter of the sinistral flank gland. Testing. The procedure for testing and scoring was similar to that described elsewhere (Noble, 1973). All tests were conducted between 1300 and 1800 hr. The testing chamber was a clear plastic cage with the same dimensions as the home cage. When tested for male behavior, the experimental female was placed in the chamber 10 min before the start of the lo-min test. A female in artificial estrus was placed in the chamber to start the test. The stimulus female was exposed briefly to coital stimulation from intact males before each test. The frequency and duration of both anogenital examination and mounting were recorded using a keyboard connected to an array of counters and timers. Linguo-genital contact was the criterion for anogenital examination and only mounts with pelvic thrusting were counted. The occurrence of the intromission pattern was recorded Females were tested for female behavior by placing them in a test chamber containing two intact males. The number of mounts preceding the first lordosis was recorded. Tests for female behavior were terminated either after the display of lordosis or after the female had received five appropriately oriented mounts.
RESULTS Anogenital examination. All androgen-treated females and five of 8 EB-treated females engaged in anogenital examination during at least one test. The duration of treatment preceding the display of anogenital examination was dependent on the hormone regimen (see Fig. 1). Seventyeight percent of the females treated with Et + DHTP, 90% of the females treated with EB t DHTP, and 100% of the females treated with TP displayed this reponse during the first test for male behavior. No EB-treated females displayed the response before the fourth test for male behavior. The total duration of anogenital examination per positive test was dependent on the hormone regimen (see Fig. 2). El + DHTP- and EB +
230
RALPH NOBLE
011OFTREATTYLWT
4
Fig. 1. The cumulative percent of females engaging in anogenital examination.
P
P
I EE
DHTP HORMONE
TP
AD
:+DHTP
I EB+GiiTP
TREATMENT
Fig. 2. The amount of time spent engaging in anogenitd examination (mean per subject per positive test f S.E.M.).
DHTP-treated females spent more time in anogenital examination than either TP- or AD-treated females (p < .Ol, Mann-Whitney v). TP- and AD-treated females spent more time in anogenital examination than either EB- or DHTP-treated females (p < .O1, Mann-Whitney v). Mounting. Several hormone regimens induced mounting (see Fig. 3). All 10 EB + DHTP-treated females mounted, in contrast to 2 of 7 DHTP-treated females (p < .OOS, Fisher’s exact probability test) and none of the EB-treated females. The percent of females mounting in both the AD-treated group (55%) and the E, + DHTP-treated group (67%) was statistically significant when compared to the EB-treated females @ < .Ol, Mann-Whitney U), but not when compared to the DHTP-treated females (p > .O.S).
FEMALE
231
MOUNTING EBtDHTP
P
DAYS OF TREATMENT
Fig. 3. The cumulative
percent of subjects mounting.
TABLE
1
The Effects of Different Hormone Regimens on the Mounting Behavior of Female Hamsters Treatment Measure
EB
DHTP
TP
AD
group E, + DHTP
EB + DHTP
N
8
7
6
9
9
10
Percent Ss mounting Percent tests
0 0
29 8
33 10
55 18
67 20
100 38
Mdn # mounts0
-
8
Mdn latency to onset of mountinga / (days of treatment)
-
27
3.5
31
5
21
2b
24
6
24
aBased only on tests during which mounting occurred. bEt + DHTP vs EB + DHTP (p < .005, Mann-Whitney U statistic).
When only data from females which did mount were examined, there were no differences among treatment groups either in the length of treatment preceding the onset of mounting or in the percent of tests during which mounting occurred (see Table 1). Females treated with E, + DHTP mounted at lower rates than the females treated with EB + DHTP @ < .02. MannWhitney U). Intromission. One of the nine E, + DHTP-treated females and eight of the ten EB + DHTP-treated females displayed the intromission pattern (p < .OOS, Fisher’s Exact Probability Test). Four of the nine AD-treated females displayed the intromission pattern. Two of the 6 TP-treated females and two of the 7 DHTP-treated females displayed the intromission pattern.
232
RALPH
NOBLE
TABLE
2
The Effects of Different Hormone Regimens on the Glans Clitoris, Flank Gland, and Body Weight Treatment Measure N Glans clitoris (mg) Mean weight S.E. Flank gland (mm) Mean length S.E. Body weight (pm) Mean weight SE.
EB 8 <2 2.0 0.0 134 11
DHTP
group
TP
AD
7
6
9
9
6.0 0.0
4.0 1.0
6.0 1.0
6.0 2.0
5.0 3.0
6.1 0.6
6.5 0.6
5.3 0.3
8.3 0.6
7.4 0.4
135 12
133 13
137 9
E, + DHTP
129 13
EB + DHTP 10
131 8
Morphological effects. There were no significant differences in body weight among treatment groups (see Table 2). All androgen-treated groups had heavier glandes clitoris than the EB-treated females, but there were no differences among androgen-treated groups. The flank glands of all androgentreated females were larger than the flank glands of EB-treated females. The:, flank glands of the AD-treated females were smaller than the flank glands of the females in the other androgen-treated groups 0, < .05, t test). Female behavior. The lordosis response was displayed by all EB-treated females, all Et + DHTP-treated females, nine of ten EB + DHTP-treated females, and none of the TP-, AD-, or DHTP-treated females.
DISCUSSION Female hamsters have the ability to perform the major components 0’; the male copulatory pattern except for the ejaculatory response. The display of the male copulatory pattern by females requires much longer periods of hormone treatment than is the case for prepuberally castrated males (Noble, 1973). 1 The effects of long-term administration of TP or EB obtained in the present study are in good agreement with the results of previous studies (Tiefer, 1970; Swanson and Crossley, 1971; Carter, Clemens, and Hoekema, 1972) and indicate that these hormone regimens are relatively ineffective in facilitating the display of mounting in female hamsters. The display of
FEMALE MOUNTING
233
mounting by a small proportion of females is a consistent finding in all studies cited. The synergistic effects of estrogen-androgen combinations on the facilitation of mounting by female hamsters is similar to the effects obtained in castrate male rats (Baum and Vreeburg, 1973; Larsson et al., 1973). Since both EB and DHTP are partially effective in male hamsters (Noble and Alsum, submitted for publication), it would appear that the substrate for the display of mounting behavior includes both estrogen-sensitive and androgen-sensitive components and that these components are present in both males and females. The differential effectiveness of AD, TP, and DHTP in facilitating the display of male behavior by females is consistent with the results obtained by Christensen et al. (Christensen, Coniglio, Paup, and Clemens, 1973) in their study of the relative effectiveness of these steroids in maintaining male behavior in castrate male hamsters. TP and AD were more effective than DHTP in inducing anogenital examination by females, while AD was more effective than TP in facilitating mounting. The relative effectiveness of AD was probably underestimated in the present study; since it was administered in the free form while the other androgens were administered in the propionate form, AD was probably available in effectively lower concentrations than either testosterone or dihydrotestosterone. The higher mount rate of EB + DHTP-treated females in comparison to the E, + DHTP indicates that the amount of mounting behavior displayed by female hamsters is dependent on either the kind or amount of estrogen available. The relative effectiveness of EB + DHTP is paradoxical since estradiol is generally regarded as the primary estrogen metabolite of testosterone (Eik-Nes, 1970), while estrone is a direct metabolite of androstenedione. The amounts of EB and E, used in the present study were both sufficient to induce the display of lordosis in all subjects when they were tested for female behavior, and to this extent the two hormone regimens were roughly equated.
ACKNOWLEDGMENTS Publication No. 13-039 of the Wisconsin Regional Primate Research Center. This investigation was supported in part by Public Health Service Training Grant No. S-TOl-HD-00104-08. It was also supported by Grant No. RR00167 from the National Institutes of Health, and Grant No. MH21312 from the National Institute of Mental Health. REFERENCES Antliff, H. R., and Young, W. C. (1956). Behavior and tissue responses of male guinea pigs to estrogens and the problem of hormone specificity. Endocrinology 61. 121-127.
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NOBLE
Baum, M. J., and Vreeburg, J. T. M. (1973). Copulation in castrated male rats following combined treatment with estradiol and dihydrotestosterone. Science 182. 283-285. Beach, F. A. (1968). Factors involved in the control of mounting by female mammals. In M. Diamond (Ed.). Perspectives in Reproduction and Sexual Behavior, pp. 83-131. Bloomington, Indiana: Indiana University Press. Christensen, L. W., Coniglio, L. P., Paup, D. C., and Clemens, L. G. (1973). Sexual behavior of male golden hamsters receiving diverse androgen treatments. Horm. Behav. 4, 223-230. Carter, C. S., Clemens, L. G., and Hoekema, D. J. (1972). Neonatal androgen and adult sexual behavior in the golden hamster. Physiol. Behav. 9, 89-95. Diamond, M. (1965). The antagonistic actions of testosterone propionate and estrogen and progesterone on copulatory patterns of the female guinea pig. Anat. Rec. 151. 449 (Abstract). Edwards, D. A., and Burge, K. B. (1971a). Early androgen treatment and male and female sexual behavior in mice. Horm. Behav. 2, 49-58. Edwards, D. A., and Burge, K. G. (1971b). Estrogenic arousal of aggressive behavior and sexual behavior in male and female mice. Horm. Behav. 2, 239-245. Eik-Nes, K. B. (1970). Synthesis and secretion of androstenedione and testosterone. In K. B. Eik-Ness, (Ed.). The Androgens of the Testes, pp. 147. New York: Marcel Dekker. Coy, R. W., and Goldfoot, D. (1973). Hormonal influences on sexually dimorphic behavior. In R. 0. Greep, (Ed.). Handbook of Physiology, Chapter 9. 169-186. Jaffe, R. B. (1969). Testosterone metabolism in target tissues: Hypothalamic and pituitary tissues of the adult rat and human fetus in the immature rat epiphyses. Steroids 14, 483-498. Larsson, K., Sodersten, P., and Beyer, C. (1973). Induction of male sexual behaviour by oestradiol benzoate in combination with dihydrotestosterone. J. Endocrinol. 57. 563-564. Naftolin, I’., Ryan, K. H., and Petro, 2. (1972). Aromatization of androstenedione by the anterior hypothalamus of adult male and female rats. Endocrinolofl 90. 295-298. Noble, R. G. (1973). The effects of castration at different intervals after birth on the _1 copulatory behavior of male hamsters (Mesocricetus auratus). Horm. Behav. 4. 45-52. Pfaff, D. (1970). Nature of sex hormone effects on rat sex behavior: Specificity of effects and individual patterns of response. J. Comp. Physiol. Pvchol. 73. 349-358. Phoenix, C. H., Goy, R. W., Gerall, A. A., and Young, W. C. (1959). Organizing actions of prenatally administered testosterone propionate on the tissues mediating behavior in the female guinea pig. Endocrinology 65, 369-382. Swanson, H. H., and Crossley, D. A. (1971). Sexual behavior in the golden hamster and its modification by neonatal administration of testosterone propionate. 111 M. Hamburgh and E. J. W. Barrington, (Eds.). Hormones in Development. pp. 677-687. New York: Appleton Press. Tiefer, L. (1970). Gonadal hormones and mating behavior in the adult golden hamster. Horm. Behav. 1, 189-202. Vandenberph, J. (1973). Effects of gonadal hormones on the flank gland of the golden hamster. Horm. Behav. 4, 28-33. Young, W. C. (1961). The hormones and mating behaviour. In W. C. Young. (Ed.). Sex and Internal Secretions, 3rd Edition. pp. 1173-1239. Baltimore: Williams and Wilkins.
Estrogen Plus Androgen Induced Mounting in Adult Female Hamsters RALPH NOBLE Wisconsin Regional Primate Research Center, Madison, Wisconsin 53 706
This study demonstrated that the combined administration of estrogens and androgens activates the display of mounting by female hamsters. Forty-nine ovariectomized hamsters were injected daily with either estradiol (DHTP, N = 7); benzoatc (EB, N = 8); dihydrotestosterone propionate testosterone propionate (TP, N = 6); androstenedione (AD, N = 9); EB plus DHTP (N = 10); or estrone plus DHTP (El + DHTP, N = 9). All androgens
were administered at a dose of 1 mg per day for the fist 24 days and at a dose of 2 mg per day for the last 14 days. The EB dose was 6pg per day and the El dose was 100 rg per day. Females were tested for male behavior once a week starting on Day 10 of injections and for female behavior on Day 39. One hundred percent of EB + DHTP treated females; 67% of the El + DHTP treated females; 55% of the AD treated females; 33% of the TP treated females; 29% of the DHTF’ treated females; and none of the EB treated females mounted during at least one test. Only one of the E, + DHTP treated females showed the intromission pattern; otherwise most females which mounted displayed the intromission pattern. The median number of days preceding the onset of mounting ranged from 21 to 31 days and did not differ among treatment groups.
Females of many mammalian species mount, and the display of mounting is facilitated by androgen administration (Young, 1961; Beach, 196s). The extent to which androgen-dependent mounting is sexually dimorphic varies across species (Coy and Goldfoot, 1973). Few female hamsters mount, and female hamsters do not respond to androgen treatment regimens which fully reinstate mounting by castrate males (Tiefer, 1970; Swanson and Cxossley, 1971; Carter, Clemens, and Hoekema, 1972). Following chronic treatment with testosterone propionate, female guinea pigs mount with a frequency approximately one-fourth the frequency displayed by comparably treated males (Phoenix, Coy, Gerall, and Young, 1959; Diamond, 1965). In the female rat, treatment with testosterone propionate results in a frequency of mounting
approximately
one-half
the 227
Copyright 0 1974 by Academic Press, Inc. All rights of reproduction in any form reserved.
frequency
displayed
by comparably
228
RALPH NOBLE
treated males (Pfaff, 1970). Male and female mice display equally high rates of mounting following administration of testosterone propionate (Edwards and Burge, 1971a). The effectiveness of other hormone regimens in facilitating mounting by females is also species dependent. Estradiol benzoate is as effective as testosterone propionate in the female rat (Pfaff, 1970), and the male mouse (Edwards and Burge, 1971b), but is totally ineffective in the female mouse (Edwards and Burge, 1971b). Female guinea pigs in either natural or induced estrus occasionally mount as much as intact males (Beach, 1968); however, chronic administration of estradiol benzoate alone does not facilitate mounting in female guinea pigs (Antliff and Young, 1956). The present study examined the possibility that the combined administration of estrogen and dihydrotestosterone facilitates the display of mounting by female hamsters. Estradiol and dihydrotestosterone interact synergistically to restore the copulatory behavior of castrate male rats (Larsson, Sodersten, and Beyer, 1973; Baum and Vreeburg, 1973).
METHODS Subjects and housing conditions. Forty-nine females were purchased from Engle’s Hamster Farm (Farmersburg, Indiana) when approximately 2 mo of age (91-100gm body weight). The females were ovariectomized using pentobarbital anaesthesia (Nembutal, 100 mg per 100 gm body weight) two weeks before the start of hormone treatments. Females were housed in translucent plastic cages (38 X 33 X 17 cm), 3-5 per cage, on a reversed light cycle (L:D, 14: 10) with the lights off from noon to 10:00 PM. Purina Rat Chow and tap water were continuously available and the corn cob bedding (Sanicel, deodor grade) was changed weekly. Design and procedure. 1 Each female was assigned to one of six groups with all the females in a cage assigned to the same group. Group 1 received daily injections of 6pg estradiol benzoate (EB, N = 8): Group 2 received dihydrotestosterone propionate (DHTP, N = 7); Group 3 received testosterone propionate (TP, N = 6); Group 4 received androstenedione (AD, N = 9): Group 5 received 6 pg EB per day plus DHTP (EB + DHTP. N = 10); and Group 6 received estrone, IOOng per day, and DHTP (Er + DHTP, N = 9). All hormones were injected subcutaneously in 0.1 ml corn oil. The androgen lThe hormones used in the present study were obtained from the following suppliers: Testosterone propionate (4-androsten-17p-al-3ane propionate), Schering Corporation; Androstenedione (A’androsten-3.17-dione). Sigma Chemical Company: Dihydrotestosterone propionate (Sa-androstan-17pol-3une propionate), Steraloids. Incorporated; Estradiol benzoate (estratrien-3.1 ‘IO-diol 3-benzoate). Steraloids. incorporated; Estrone (A’ ,3*5 (I 6)+stratrien-301-l ‘l-one). Sigma Chemical Company.
FEMALE MOUNTING
229
dose was 1 mg per day for 24 days, followed by daily injections of 2 mg per day from Day 25 to Day 38. Females were tested for male behavior once a week starting ten days after the first injection. The day after the last test for male behavior, females were tested for the display of lordosis. Then three females from each group were sacrificed using an overdose of sodium pentobarbital and the glandes clitoris removed using a dissecting microscope and weighed (wet weight) to the nearest milligram using a Mettler H20 balance. At the end of the experiment, the flank glands of all females were measured using the procedure described by Vandenbergh (1973) to determine the longest diameter of the sinistral flank gland. Testing. The procedure for testing and scoring was similar to that described elsewhere (Noble, 1973). All tests were conducted between 1300 and 1800 hr. The testing chamber was a clear plastic cage with the same dimensions as the home cage. When tested for male behavior, the experimental female was placed in the chamber 10 min before the start of the lo-min test. A female in artificial estrus was placed in the chamber to start the test. The stimulus female was exposed briefly to coital stimulation from intact males before each test. The frequency and duration of both anogenital examination and mounting were recorded using a keyboard connected to an array of counters and timers. Linguo-genital contact was the criterion for anogenital examination and only mounts with pelvic thrusting were counted. The occurrence of the intromission pattern was recorded Females were tested for female behavior by placing them in a test chamber containing two intact males. The number of mounts preceding the first lordosis was recorded. Tests for female behavior were terminated either after the display of lordosis or after the female had received five appropriately oriented mounts.
RESULTS Anogenital examination. All androgen-treated females and five of 8 EB-treated females engaged in anogenital examination during at least one test. The duration of treatment preceding the display of anogenital examination was dependent on the hormone regimen (see Fig. 1). Seventyeight percent of the females treated with Et + DHTP, 90% of the females treated with EB t DHTP, and 100% of the females treated with TP displayed this reponse during the first test for male behavior. No EB-treated females displayed the response before the fourth test for male behavior. The total duration of anogenital examination per positive test was dependent on the hormone regimen (see Fig. 2). El + DHTP- and EB +
230
RALPH NOBLE
011OFTREATTYLWT
4
Fig. 1. The cumulative percent of females engaging in anogenital examination.
P
P
I EE
DHTP HORMONE
TP
AD
:+DHTP
I EB+GiiTP
TREATMENT
Fig. 2. The amount of time spent engaging in anogenitd examination (mean per subject per positive test f S.E.M.).
DHTP-treated females spent more time in anogenital examination than either TP- or AD-treated females (p < .Ol, Mann-Whitney v). TP- and AD-treated females spent more time in anogenital examination than either EB- or DHTP-treated females (p < .O1, Mann-Whitney v). Mounting. Several hormone regimens induced mounting (see Fig. 3). All 10 EB + DHTP-treated females mounted, in contrast to 2 of 7 DHTP-treated females (p < .OOS, Fisher’s exact probability test) and none of the EB-treated females. The percent of females mounting in both the AD-treated group (55%) and the E, + DHTP-treated group (67%) was statistically significant when compared to the EB-treated females @ < .Ol, Mann-Whitney U), but not when compared to the DHTP-treated females (p > .O.S).
FEMALE
231
MOUNTING EBtDHTP
P
DAYS OF TREATMENT
Fig. 3. The cumulative
percent of subjects mounting.
TABLE
1
The Effects of Different Hormone Regimens on the Mounting Behavior of Female Hamsters Treatment Measure
EB
DHTP
TP
AD
group E, + DHTP
EB + DHTP
N
8
7
6
9
9
10
Percent Ss mounting Percent tests
0 0
29 8
33 10
55 18
67 20
100 38
Mdn # mounts0
-
8
Mdn latency to onset of mountinga / (days of treatment)
-
27
3.5
31
5
21
2b
24
6
24
aBased only on tests during which mounting occurred. bEt + DHTP vs EB + DHTP (p < .005, Mann-Whitney U statistic).
When only data from females which did mount were examined, there were no differences among treatment groups either in the length of treatment preceding the onset of mounting or in the percent of tests during which mounting occurred (see Table 1). Females treated with E, + DHTP mounted at lower rates than the females treated with EB + DHTP @ < .02. MannWhitney U). Intromission. One of the nine E, + DHTP-treated females and eight of the ten EB + DHTP-treated females displayed the intromission pattern (p < .OOS, Fisher’s Exact Probability Test). Four of the nine AD-treated females displayed the intromission pattern. Two of the 6 TP-treated females and two of the 7 DHTP-treated females displayed the intromission pattern.
232
RALPH
NOBLE
TABLE
2
The Effects of Different Hormone Regimens on the Glans Clitoris, Flank Gland, and Body Weight Treatment Measure N Glans clitoris (mg) Mean weight S.E. Flank gland (mm) Mean length S.E. Body weight (pm) Mean weight SE.
EB 8 <2 2.0 0.0 134 11
DHTP
group
TP
AD
7
6
9
9
6.0 0.0
4.0 1.0
6.0 1.0
6.0 2.0
5.0 3.0
6.1 0.6
6.5 0.6
5.3 0.3
8.3 0.6
7.4 0.4
135 12
133 13
137 9
E, + DHTP
129 13
EB + DHTP 10
131 8
Morphological effects. There were no significant differences in body weight among treatment groups (see Table 2). All androgen-treated groups had heavier glandes clitoris than the EB-treated females, but there were no differences among androgen-treated groups. The flank glands of all androgentreated females were larger than the flank glands of EB-treated females. The:, flank glands of the AD-treated females were smaller than the flank glands of the females in the other androgen-treated groups 0, < .05, t test). Female behavior. The lordosis response was displayed by all EB-treated females, all Et + DHTP-treated females, nine of ten EB + DHTP-treated females, and none of the TP-, AD-, or DHTP-treated females.
DISCUSSION Female hamsters have the ability to perform the major components 0’; the male copulatory pattern except for the ejaculatory response. The display of the male copulatory pattern by females requires much longer periods of hormone treatment than is the case for prepuberally castrated males (Noble, 1973). 1 The effects of long-term administration of TP or EB obtained in the present study are in good agreement with the results of previous studies (Tiefer, 1970; Swanson and Crossley, 1971; Carter, Clemens, and Hoekema, 1972) and indicate that these hormone regimens are relatively ineffective in facilitating the display of mounting in female hamsters. The display of
FEMALE MOUNTING
233
mounting by a small proportion of females is a consistent finding in all studies cited. The synergistic effects of estrogen-androgen combinations on the facilitation of mounting by female hamsters is similar to the effects obtained in castrate male rats (Baum and Vreeburg, 1973; Larsson et al., 1973). Since both EB and DHTP are partially effective in male hamsters (Noble and Alsum, submitted for publication), it would appear that the substrate for the display of mounting behavior includes both estrogen-sensitive and androgen-sensitive components and that these components are present in both males and females. The differential effectiveness of AD, TP, and DHTP in facilitating the display of male behavior by females is consistent with the results obtained by Christensen et al. (Christensen, Coniglio, Paup, and Clemens, 1973) in their study of the relative effectiveness of these steroids in maintaining male behavior in castrate male hamsters. TP and AD were more effective than DHTP in inducing anogenital examination by females, while AD was more effective than TP in facilitating mounting. The relative effectiveness of AD was probably underestimated in the present study; since it was administered in the free form while the other androgens were administered in the propionate form, AD was probably available in effectively lower concentrations than either testosterone or dihydrotestosterone. The higher mount rate of EB + DHTP-treated females in comparison to the E, + DHTP indicates that the amount of mounting behavior displayed by female hamsters is dependent on either the kind or amount of estrogen available. The relative effectiveness of EB + DHTP is paradoxical since estradiol is generally regarded as the primary estrogen metabolite of testosterone (Eik-Nes, 1970), while estrone is a direct metabolite of androstenedione. The amounts of EB and E, used in the present study were both sufficient to induce the display of lordosis in all subjects when they were tested for female behavior, and to this extent the two hormone regimens were roughly equated.
ACKNOWLEDGMENTS Publication No. 13-039 of the Wisconsin Regional Primate Research Center. This investigation was supported in part by Public Health Service Training Grant No. S-TOl-HD-00104-08. It was also supported by Grant No. RR00167 from the National Institutes of Health, and Grant No. MH21312 from the National Institute of Mental Health. REFERENCES Antliff, H. R., and Young, W. C. (1956). Behavior and tissue responses of male guinea pigs to estrogens and the problem of hormone specificity. Endocrinology 61. 121-127.
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Baum, M. J., and Vreeburg, J. T. M. (1973). Copulation in castrated male rats following combined treatment with estradiol and dihydrotestosterone. Science 182. 283-285. Beach, F. A. (1968). Factors involved in the control of mounting by female mammals. In M. Diamond (Ed.). Perspectives in Reproduction and Sexual Behavior, pp. 83-131. Bloomington, Indiana: Indiana University Press. Christensen, L. W., Coniglio, L. P., Paup, D. C., and Clemens, L. G. (1973). Sexual behavior of male golden hamsters receiving diverse androgen treatments. Horm. Behav. 4, 223-230. Carter, C. S., Clemens, L. G., and Hoekema, D. J. (1972). Neonatal androgen and adult sexual behavior in the golden hamster. Physiol. Behav. 9, 89-95. Diamond, M. (1965). The antagonistic actions of testosterone propionate and estrogen and progesterone on copulatory patterns of the female guinea pig. Anat. Rec. 151. 449 (Abstract). Edwards, D. A., and Burge, K. B. (1971a). Early androgen treatment and male and female sexual behavior in mice. Horm. Behav. 2, 49-58. Edwards, D. A., and Burge, K. G. (1971b). Estrogenic arousal of aggressive behavior and sexual behavior in male and female mice. Horm. Behav. 2, 239-245. Eik-Nes, K. B. (1970). Synthesis and secretion of androstenedione and testosterone. In K. B. Eik-Ness, (Ed.). The Androgens of the Testes, pp. 147. New York: Marcel Dekker. Coy, R. W., and Goldfoot, D. (1973). Hormonal influences on sexually dimorphic behavior. In R. 0. Greep, (Ed.). Handbook of Physiology, Chapter 9. 169-186. Jaffe, R. B. (1969). Testosterone metabolism in target tissues: Hypothalamic and pituitary tissues of the adult rat and human fetus in the immature rat epiphyses. Steroids 14, 483-498. Larsson, K., Sodersten, P., and Beyer, C. (1973). Induction of male sexual behaviour by oestradiol benzoate in combination with dihydrotestosterone. J. Endocrinol. 57. 563-564. Naftolin, I’., Ryan, K. H., and Petro, 2. (1972). Aromatization of androstenedione by the anterior hypothalamus of adult male and female rats. Endocrinolofl 90. 295-298. Noble, R. G. (1973). The effects of castration at different intervals after birth on the _1 copulatory behavior of male hamsters (Mesocricetus auratus). Horm. Behav. 4. 45-52. Pfaff, D. (1970). Nature of sex hormone effects on rat sex behavior: Specificity of effects and individual patterns of response. J. Comp. Physiol. Pvchol. 73. 349-358. Phoenix, C. H., Goy, R. W., Gerall, A. A., and Young, W. C. (1959). Organizing actions of prenatally administered testosterone propionate on the tissues mediating behavior in the female guinea pig. Endocrinology 65, 369-382. Swanson, H. H., and Crossley, D. A. (1971). Sexual behavior in the golden hamster and its modification by neonatal administration of testosterone propionate. 111 M. Hamburgh and E. J. W. Barrington, (Eds.). Hormones in Development. pp. 677-687. New York: Appleton Press. Tiefer, L. (1970). Gonadal hormones and mating behavior in the adult golden hamster. Horm. Behav. 1, 189-202. Vandenberph, J. (1973). Effects of gonadal hormones on the flank gland of the golden hamster. Horm. Behav. 4, 28-33. Young, W. C. (1961). The hormones and mating behaviour. In W. C. Young. (Ed.). Sex and Internal Secretions, 3rd Edition. pp. 1173-1239. Baltimore: Williams and Wilkins.