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Uncovering rhythms in serum gastrin
JOURNAL
OF SURGICAL
RESEARCH
24, 380-383
Uncovering
(19/i,,
Rhythms
in Serum Gastrinl
RICHARD P. SAIK, M.D.,* NATHANIEL WEISENFELD, M.D., A. GERSON GREENBURG, M.D., DANIEL KRIPKE, M.D., ANDGERALD PESKIN, M.D. Department
of Surgery,
Veterans Administration Hospital and University San Diego, California 92161 Submitted
for publication
Secretion of many peptide hormones occurs with a biological rhythm. In man, rhythms of acid output have been documented, but without corresponding rhythms in serum gastrin [7]. Variations in gastrin are most commonly related to feeding [3] and may be overshadowed by intraluminal acid and pH changes [4]. In order to uncover rhythms, unencumbered by the influence of feeding, and to assess the importance of diverting acid from the antrum, this canine study was undertaken.
Three groups of mongrel dogs were investigated by sampling peripheral serum gastrin levels, basally and every 2 hr for 24-hr periods. Group I consisted of four normal dogs; Group II consisted of three dogs in whom an innervated but exteriorized antral pouch was placed onto the abdominal wall; and Group III consisted of five dogs with innervated antral pouches explanted onto the transverse colon in order to achieve a hypergastrinemic state. All dogs were conditioned, weighed 15-25 kg, and were operated on under a pentobarbitol anesthetic. Anatomical antral demarcation was determined using congo red. All animals
Group 1. The normal dogs tested on eight occasions revealed a consistent circadian rhythm in gastrin (Fig. 1) as evidenced by phase angle distribution (all subjects fell within 180”, P < 0.01, Rayleigh test). The mean peak was O”, i.e., the start of the experiment. Examination of the raw data indicates that this is the true rhythm, not an effect of experimental initiation, since final gastrin values were essentially the same as 380
8 1978 by Academic Press, Inc. of reproduction in any form reserved.
7, 1977
RESULTS
1 Supported in part by the ResearchService of the Veterans Administration Hospital and USPHS Grant No. AM 17960. 2 Address reprint requests to Richard P. Saik, M.D., Veterans Administration Hospital, 112E, 3350 La Jolla Village Drive, San Diego, California 92161.
Copyright All rights
San Diego,
were allowed a 4week recovery period and had been eating a normal diet for 3 weeks before testing. Dogs were fasted and allowed only water on the day prior to study and each was studied for two separate 24-hr periods. Serum gastrin determinations were performed by our standard radioimmunoassay using antibody produced in white New Zealand rabbits to synthetic human gastrin I. Statistical Methods. Twenty-four-hour gastrin values for each group of dogs were analyzed by establishing a cosine curve best fitting the gastrin values for each individual experiment, as estimated by a least-squares method [5]. From the fitted cosine, the phase (acrophase) was derived as referenced to the starting point of sampling (10:00 AM). Any consistent circadian rhythm in gastrin for any group would be reflected by consistent, fitted phases, whereas nonrhythm peaks would occur in a random manner. Consistency of phase was tested for significance by the Rayleigh test [l].
METHODS
0022-4804/78/0245-0380$01.00/O
November
of California,
381
SAIK ET AL.: RHYTHMS IN SERUM GASTRIN DOG 5 NORMAL
NORMALS PHASE ANGLE DlSTRlEUTlON
+‘l -I’
IO a.m.
I 10 0-m
IO pm HOURS
FIG. 3. Representative curve for one dog (Dog 5)
FIG. 1. Phase angle for the occurrence peak gastritis in normal dogs. 0” represents 1090 AM or start of sampling. Distribution is not random (P < 0.05, Rayleigh test).
with best-fitted cosine curve from which phase angle is calculated.
5) and no biological rhythm as illustrated in the raw data for one typical experiment (Fig. 6). Group ZZZ. In the dogs with an antral pouch explanted onto the colon, a consistently elevated serum gastrin (levels more than double preoperative levels) was noted (Fig. 7), but no significant trend in phase differences was noted (Fig. 8).
initial gastrins. The mean curve for normal dogs (Fig. 2) revealed that peak gastrins were about twice those of the trough indicating a 100% circadian amplitude. A sample rhythm of one dog (normalized by expressing percentage deviation from the mean) is illustrated in Fig. 3 and raw data in Fig. 4. Group ZZ. The three dogs in whom an DISCUSSION innervated antral pouch was exteriorized A circadian rhythm of gastrin definitely and thus removed from the effects of acidity exists in normal fasted mongrel dogs. This revealed a random phase distribution (Fig. rhythm is abolished when the innervated NORMAL antrum is freed of basal gastric acid secretion and when the innervated antrum is placed under continuous maximal stimula‘/ tion. This data suggests that gastrin rhythms are dependent on intraluminal pH and are independent per se of vagal activity except as this activity may affect acid output. Other investigators have uncovered variations in humans which have been mostly
I0o.m
I0p.m
loam
HOURS
FIG. 2. Mean percentage deiviation from the mean gastrin in normal dogs.
FIG. 4. Gastrin levels in picograms/milliliter illustrative normal dog.
in one
382
JOURNAL OF SURGICAL RESEARCH: VOL. 24, NO. 5, MAY 1978 POUCH
1200
DISTRIEUTION
1100
EXTERIORIZED PHASE ANGLE
EXPLANTED COLON WUCH
1000
167 169 HOURS
FIG. 7. Gastrin levels in picograms/milliliter in one illustrative dog with an explanted ant& pouch onto the colon.
In order to study the gastrin rhythm, free of acid and/or consistently stimulated by a more alkaline pH, we examined an antral pouch preparation in dogs. As expected, antral distention with constant alkalinizathe result of ingestion of food [3, 7, 111. tion caused a marked hypergastrininemia Recently a difference between ulcer patients which seems to have obscured any rhythm. and normals have been detected by Tarquini Diverting acid by an antral explanation and et al. [ll]. The lack of a gastrin rhythm in gastroduodenostomy eliminated the circadian ulcer patients which is present in normal rhythm noted in our normal animals, subjects suggests a defect in autoregula- suggesting that pH variations, in fact, tion which may normally be operative. control fluctuations in serum gastrin. Rhythms, apart from the response to meals, Physiological distention of the antrum may have not before been noted in either normal also play a role in the circadian release or ulcer patients, although gastrin levels dif- of gastrin in normals. fered [S]. Basal acid outputs, however, Since basal serum gastrin is largely have been noted to fluctuate with a bio- composed of the larger molecular forms and rhythm [2, 7, 91, and it has been suggested tissue antral gastrin of G-17, smaller variathat constant removal of gastric acid may, in fact, uncover gastrin rhythms which EXPLANTED COLONPOUCH PHASE ANGLE OISTRIBUTION otherwise may be physiologically inhibited by acid bathing the antrum [4]. In one study [7], intubation did not result in gastrin rhythms being noted, but complete removal of acid with a tube is difficult, not easily documented, and still may not affect mucosal pH [6].
5. Phase angle for the occurrence of peak gastrins in the dogs with exteriorized antral pouches. Distribution is random (P > 0.05, Rayleigh test). FIG.
242
FIG. 6. Gastrin levels in picogramsimilliliter in one illustrative dog with an exteriorized antral pouch.
27; :76
8. Phase angle for the occurrence of peak gastrins in the dogs with explanted antral pouches onto the colon. Distribution is random (P > 0.05, Rayleigh test). FIG.
SAIK ET AL.: RHYTHMS IN SERUM GASTRIN
tions of antral release may not easily be detected by measuring total serum gastrin values, although dog duodenal gastrin is less of the total amount than in man [lo, 111. At this point, it appears that a definite circadian gastrin rhythm exists in the normal dog, which is abolished by removing the antrum from the acid stream or by constant stimulation. If central control exists, it primarily works via vagal effects on intraluminal pH. Experimental gastrin sampling, in the dog, at least, must be taken at consistent times of the day since 100%variations are noted over a 24-hr period in a basal animal. SUMMARY
A definite circadian rhythm in serum gastrin, as measured every 2 hr for 24 hr, exists in the normal fasted dog. This rhythm is abolished by removing acid and pH effects by explanting the innervated antrum onto the abdomen or stimulating by explanting onto the colon. Twofold variations in serum gastrin during a day occur in a cyclic nature and are presumably secondary to variations in intraluminal pH. ACKNOWLEDGMENT The authors would like to thank Mr. Douglas McClure for his analysis and preparation of the data.
1. Batschelet, Analysis
E. Statistical
Rhythms. Washington: American Institute of Biological Sciences, 1965. p. 28. Breuhaus, H., Akre, O., and Everley, H. Nocturnal gastric secretions in normal and duodenal ulcer patients on various forms of therapy. Gastroenterology 16, 172, 1950. Feurle, G., Ketterer, H., Becker, H., and Creutzfeldt , W. Circadian serum gastrin concentrations in control persons and patients with ulcer disease. Certain Biological
Stand. .I. Gastroenterol. 7: 117, 1972. 4. Ganguli, P., and Forrester, J. Circadian rhythm and plasma levels of gastrin. Nature Nebv Biol.
236: 127, 1972. F., Johnson, E., Nelson, W., and Southern, R. Autorthythmometry procedures for physiologic self-measurements and their analysis. Physiol. Teacher 1: 1, 1972. Levine, B., Greenburg, A. G., Peskin, G., and Saik, R. P. Antral gastrin regulation. J. Surg. Res. 20: SO9, 1976. Moore, J. G., and Wolfe, M. Circadian plasma gastrin patterns in feeding and fasted man. Digestion 11: 226, 1974. Russell, R., Ellis, B., Evans, P., and Phillips, P. The twenty-four hour pattern of gastrin levels in normal subjects and duodenal ulcer patients. Presented at the 3rd Tripartite Meeting of the Society of University Surgeons, Philadelphia, September 1976. 9. Stacher, G., Presslich, G., and Starkes, H. Gastric acid secretion and sleep stages during nocturnal night sleep. Gastroenterology 68: 1449, 1975. 10. Straus, E., and Yalow, T. Studies on the distribution and degradation of heptadecapeptide, big, and big, big, gastrin. Gastroenterulogy 68: 1449, 1975. 11. Tarquini, B., Brocchi, A., Buricchi, L., Cappelli, G., Costa, A., Neri, B., and Cagnoni, M. Circadian study on serum gastrin in patients with duodenal ulcer and in a control group. Chrono5. Halberg,
biology
REFERENCES Methods
for
of Problems in Animal Orientation
the and
383
4: 49, 1977.
12. Yale, T., and Wu, N. Additional studies on the nature of big, big, gastrin. Gastroenterology 65: 19. 1973.
OF SURGICAL
RESEARCH
24, 380-383
Uncovering
(19/i,,
Rhythms
in Serum Gastrinl
RICHARD P. SAIK, M.D.,* NATHANIEL WEISENFELD, M.D., A. GERSON GREENBURG, M.D., DANIEL KRIPKE, M.D., ANDGERALD PESKIN, M.D. Department
of Surgery,
Veterans Administration Hospital and University San Diego, California 92161 Submitted
for publication
Secretion of many peptide hormones occurs with a biological rhythm. In man, rhythms of acid output have been documented, but without corresponding rhythms in serum gastrin [7]. Variations in gastrin are most commonly related to feeding [3] and may be overshadowed by intraluminal acid and pH changes [4]. In order to uncover rhythms, unencumbered by the influence of feeding, and to assess the importance of diverting acid from the antrum, this canine study was undertaken.
Three groups of mongrel dogs were investigated by sampling peripheral serum gastrin levels, basally and every 2 hr for 24-hr periods. Group I consisted of four normal dogs; Group II consisted of three dogs in whom an innervated but exteriorized antral pouch was placed onto the abdominal wall; and Group III consisted of five dogs with innervated antral pouches explanted onto the transverse colon in order to achieve a hypergastrinemic state. All dogs were conditioned, weighed 15-25 kg, and were operated on under a pentobarbitol anesthetic. Anatomical antral demarcation was determined using congo red. All animals
Group 1. The normal dogs tested on eight occasions revealed a consistent circadian rhythm in gastrin (Fig. 1) as evidenced by phase angle distribution (all subjects fell within 180”, P < 0.01, Rayleigh test). The mean peak was O”, i.e., the start of the experiment. Examination of the raw data indicates that this is the true rhythm, not an effect of experimental initiation, since final gastrin values were essentially the same as 380
8 1978 by Academic Press, Inc. of reproduction in any form reserved.
7, 1977
RESULTS
1 Supported in part by the ResearchService of the Veterans Administration Hospital and USPHS Grant No. AM 17960. 2 Address reprint requests to Richard P. Saik, M.D., Veterans Administration Hospital, 112E, 3350 La Jolla Village Drive, San Diego, California 92161.
Copyright All rights
San Diego,
were allowed a 4week recovery period and had been eating a normal diet for 3 weeks before testing. Dogs were fasted and allowed only water on the day prior to study and each was studied for two separate 24-hr periods. Serum gastrin determinations were performed by our standard radioimmunoassay using antibody produced in white New Zealand rabbits to synthetic human gastrin I. Statistical Methods. Twenty-four-hour gastrin values for each group of dogs were analyzed by establishing a cosine curve best fitting the gastrin values for each individual experiment, as estimated by a least-squares method [5]. From the fitted cosine, the phase (acrophase) was derived as referenced to the starting point of sampling (10:00 AM). Any consistent circadian rhythm in gastrin for any group would be reflected by consistent, fitted phases, whereas nonrhythm peaks would occur in a random manner. Consistency of phase was tested for significance by the Rayleigh test [l].
METHODS
0022-4804/78/0245-0380$01.00/O
November
of California,
381
SAIK ET AL.: RHYTHMS IN SERUM GASTRIN DOG 5 NORMAL
NORMALS PHASE ANGLE DlSTRlEUTlON
+‘l -I’
IO a.m.
I 10 0-m
IO pm HOURS
FIG. 3. Representative curve for one dog (Dog 5)
FIG. 1. Phase angle for the occurrence peak gastritis in normal dogs. 0” represents 1090 AM or start of sampling. Distribution is not random (P < 0.05, Rayleigh test).
with best-fitted cosine curve from which phase angle is calculated.
5) and no biological rhythm as illustrated in the raw data for one typical experiment (Fig. 6). Group ZZZ. In the dogs with an antral pouch explanted onto the colon, a consistently elevated serum gastrin (levels more than double preoperative levels) was noted (Fig. 7), but no significant trend in phase differences was noted (Fig. 8).
initial gastrins. The mean curve for normal dogs (Fig. 2) revealed that peak gastrins were about twice those of the trough indicating a 100% circadian amplitude. A sample rhythm of one dog (normalized by expressing percentage deviation from the mean) is illustrated in Fig. 3 and raw data in Fig. 4. Group ZZ. The three dogs in whom an DISCUSSION innervated antral pouch was exteriorized A circadian rhythm of gastrin definitely and thus removed from the effects of acidity exists in normal fasted mongrel dogs. This revealed a random phase distribution (Fig. rhythm is abolished when the innervated NORMAL antrum is freed of basal gastric acid secretion and when the innervated antrum is placed under continuous maximal stimula‘/ tion. This data suggests that gastrin rhythms are dependent on intraluminal pH and are independent per se of vagal activity except as this activity may affect acid output. Other investigators have uncovered variations in humans which have been mostly
I0o.m
I0p.m
loam
HOURS
FIG. 2. Mean percentage deiviation from the mean gastrin in normal dogs.
FIG. 4. Gastrin levels in picograms/milliliter illustrative normal dog.
in one
382
JOURNAL OF SURGICAL RESEARCH: VOL. 24, NO. 5, MAY 1978 POUCH
1200
DISTRIEUTION
1100
EXTERIORIZED PHASE ANGLE
EXPLANTED COLON WUCH
1000
167 169 HOURS
FIG. 7. Gastrin levels in picograms/milliliter in one illustrative dog with an explanted ant& pouch onto the colon.
In order to study the gastrin rhythm, free of acid and/or consistently stimulated by a more alkaline pH, we examined an antral pouch preparation in dogs. As expected, antral distention with constant alkalinizathe result of ingestion of food [3, 7, 111. tion caused a marked hypergastrininemia Recently a difference between ulcer patients which seems to have obscured any rhythm. and normals have been detected by Tarquini Diverting acid by an antral explanation and et al. [ll]. The lack of a gastrin rhythm in gastroduodenostomy eliminated the circadian ulcer patients which is present in normal rhythm noted in our normal animals, subjects suggests a defect in autoregula- suggesting that pH variations, in fact, tion which may normally be operative. control fluctuations in serum gastrin. Rhythms, apart from the response to meals, Physiological distention of the antrum may have not before been noted in either normal also play a role in the circadian release or ulcer patients, although gastrin levels dif- of gastrin in normals. fered [S]. Basal acid outputs, however, Since basal serum gastrin is largely have been noted to fluctuate with a bio- composed of the larger molecular forms and rhythm [2, 7, 91, and it has been suggested tissue antral gastrin of G-17, smaller variathat constant removal of gastric acid may, in fact, uncover gastrin rhythms which EXPLANTED COLONPOUCH PHASE ANGLE OISTRIBUTION otherwise may be physiologically inhibited by acid bathing the antrum [4]. In one study [7], intubation did not result in gastrin rhythms being noted, but complete removal of acid with a tube is difficult, not easily documented, and still may not affect mucosal pH [6].
5. Phase angle for the occurrence of peak gastrins in the dogs with exteriorized antral pouches. Distribution is random (P > 0.05, Rayleigh test). FIG.
242
FIG. 6. Gastrin levels in picogramsimilliliter in one illustrative dog with an exteriorized antral pouch.
27; :76
8. Phase angle for the occurrence of peak gastrins in the dogs with explanted antral pouches onto the colon. Distribution is random (P > 0.05, Rayleigh test). FIG.
SAIK ET AL.: RHYTHMS IN SERUM GASTRIN
tions of antral release may not easily be detected by measuring total serum gastrin values, although dog duodenal gastrin is less of the total amount than in man [lo, 111. At this point, it appears that a definite circadian gastrin rhythm exists in the normal dog, which is abolished by removing the antrum from the acid stream or by constant stimulation. If central control exists, it primarily works via vagal effects on intraluminal pH. Experimental gastrin sampling, in the dog, at least, must be taken at consistent times of the day since 100%variations are noted over a 24-hr period in a basal animal. SUMMARY
A definite circadian rhythm in serum gastrin, as measured every 2 hr for 24 hr, exists in the normal fasted dog. This rhythm is abolished by removing acid and pH effects by explanting the innervated antrum onto the abdomen or stimulating by explanting onto the colon. Twofold variations in serum gastrin during a day occur in a cyclic nature and are presumably secondary to variations in intraluminal pH. ACKNOWLEDGMENT The authors would like to thank Mr. Douglas McClure for his analysis and preparation of the data.
1. Batschelet, Analysis
E. Statistical
Rhythms. Washington: American Institute of Biological Sciences, 1965. p. 28. Breuhaus, H., Akre, O., and Everley, H. Nocturnal gastric secretions in normal and duodenal ulcer patients on various forms of therapy. Gastroenterology 16, 172, 1950. Feurle, G., Ketterer, H., Becker, H., and Creutzfeldt , W. Circadian serum gastrin concentrations in control persons and patients with ulcer disease. Certain Biological
Stand. .I. Gastroenterol. 7: 117, 1972. 4. Ganguli, P., and Forrester, J. Circadian rhythm and plasma levels of gastrin. Nature Nebv Biol.
236: 127, 1972. F., Johnson, E., Nelson, W., and Southern, R. Autorthythmometry procedures for physiologic self-measurements and their analysis. Physiol. Teacher 1: 1, 1972. Levine, B., Greenburg, A. G., Peskin, G., and Saik, R. P. Antral gastrin regulation. J. Surg. Res. 20: SO9, 1976. Moore, J. G., and Wolfe, M. Circadian plasma gastrin patterns in feeding and fasted man. Digestion 11: 226, 1974. Russell, R., Ellis, B., Evans, P., and Phillips, P. The twenty-four hour pattern of gastrin levels in normal subjects and duodenal ulcer patients. Presented at the 3rd Tripartite Meeting of the Society of University Surgeons, Philadelphia, September 1976. 9. Stacher, G., Presslich, G., and Starkes, H. Gastric acid secretion and sleep stages during nocturnal night sleep. Gastroenterology 68: 1449, 1975. 10. Straus, E., and Yalow, T. Studies on the distribution and degradation of heptadecapeptide, big, and big, big, gastrin. Gastroenterulogy 68: 1449, 1975. 11. Tarquini, B., Brocchi, A., Buricchi, L., Cappelli, G., Costa, A., Neri, B., and Cagnoni, M. Circadian study on serum gastrin in patients with duodenal ulcer and in a control group. Chrono5. Halberg,
biology
REFERENCES Methods
for
of Problems in Animal Orientation
the and
383
4: 49, 1977.
12. Yale, T., and Wu, N. Additional studies on the nature of big, big, gastrin. Gastroenterology 65: 19. 1973.