Diurnal variations in serum testosterone concentrations of captive adult male chacma baboons (Papio ursinus).код для вставкиСкачать
American Journal of Primatology 1:421-425 (1981) Diurnal Variations in Serum Testosterone Concentrations of Captive Adult Male Chacma Baboons (Papio ursinus) C. BIELERT Primate Behaviour Research Group and Department o f Psychology, University o f the Witwatersrand, Johannesburg, South Africa M. E. HOWARD-TRIPP Central Animal Unit, University of the Witwatersrand, Johannesburg, South Afnca L. A. VAN DER WALT Endocrinology Unit,The South African Institute for Medical Research and Uniuersity o f the Witwatersrand, Johannesburg South Africa Captive adult male chacma baboons (Papio ursinus) housed with natural lighting exposure and blood sampled at 3-hr intervals showed significant diurnal variations in serum testosterone concentrations. Low mean concentrations were found at 0800 hr approximately 1 hr after sunrise and mean concentrations were their highest at 2000 hr approximately 1 ?A hr after sunset. Key words: circadian, diurnal variation, serum testosterone, chacma baboon, Pupio ursinus INTRODUCTION Studies on testosterone levels in nonprimate species such as rats, mice [Bartke et al, 19751, and bulls [Sanwal et al, 19741 have failed to demonstrate a clearcut circadian rhythm. In marked contrast, diurnal rhythms in peripheral testosterone concentrations have now been reported for a number of primates, including prosimians [Galago crassicuudutus, Van Hornet al, 1976; Lemur catta, Van Hornet al, 19761, catarrhine monkeys (Cercopithecus sp., Beattie & Bullock, 1978; Macaca muluttu, Goodman et al, 1974; Michael et al, 1974; Perachio, et al, 1977; Macaca fuscicuhris, Steiner, et al, 19801, and man [Resko & Eik-Nes, 1966; Lacerda et al, 1973; Judd et al, 19741. Only recently, however, was a study carried out on diurnal variation under conditions more typical of those found in nature [Rose et al, 19781. Relatively few data on endocrine parameters of the male baboon are available although studies have been published on the plasma levels of unconjugated steroids [Aso et al, 19761 and the urinary steroid excretion and conjugation [Setchell et al, 19761 of the hamadryas or sacred baboon (Papio humdry a s) . In addition there is one study on the androgen metabolism of the yellow baboon (Pupio cyunocephalus) Bamamoto et al, 19781. As part of an ongoing program examining the relationships between gonadal hormones and sociosexual behavior in the chacma baboon (Pupio ursinus), it was felt Received April 24, 1981: accepted June 25. 1981. Address reprint requests to C. Bielert, Department of Psychology, University of Witwatersrand, 1 Jan Smuts Avenue, Johannesburg 2001, South Africa. 0275-2565/81/0104-0421$02.00 0 1981 Alan R. Liss, Inc. 422 Bielert, Howard-Tripp, and van der Walt appropriate to examine the possible diurnal fluctuations which males may show in their serum testosterone levels. MATERIALS AND METHODS Subjects A total of six adult wild caught male chacma baboons (Nos. 3,6,14,15,532,655)were subjects in this experiment. They had all been caught in the Waterberg area of the northern Transvaal near Vaalwater, South Africa. Their adult status was attested to by full dentition and adult weight. They had all been housed in the colony under the conditions to be described for a minimum of five years. Housing and Care The subjects were all individually caged in squeeze cages. Cage dimensions were .91 X .91 X 1.9 m and each cage was equipped with a sitting shelf approximately 94 cm. above the cage bottom extending out into the cage about 30 cm. With the removal of the food and water dishes, the cage could be collapsed into a cube. All animals were fed daily at 1400 hr on a commercially prepared pellet. [Epol (Pty) Ltd., P.O. Box 19096, Pretoria West, 0117, South Africa.] Their prepared ration was supplemented three times a week with fresh fruit or vegetables and water was available ad libitum. At no time were the animals involved in any other experiments. During the experimental period no animal required any medical care. The males were housed together in a room of dimensions 10 X 9 X 3.5 m. No female baboons were housed in this same room and at no time were any of the males exposed to females. In addition to the room having glass windows, the animal house roof has fiberglass panels which ensure natural lighting influences and allow the animals to adjust to seasonal day length. The animals were not exposed to anything other than a natural day length except that electric lights were used briefly during nocturnal blood draws. Blood Collection and Testosterone Assay On March 10, 1979, at 0200 hr, blood collection was begun. For this procedure the males' cages were collapsed; the males were then restrained and given an intramuscular injection (1 mgikg) of phencyclidine (1-[l-phencyclohexyl]piperidine)hydrochloride. Although the possible effects of this drug on the peripheral testosterone levels of male baboons are unknown, it has been demonstrated that brief daily periods of sedation with this drug did not interfere with the menstrual cycle of female rhesus monkeys (Macaca mulattu) [Ferin et al, 19761. When immobilized, the males were removed from their cages and, using standard asceptic techniques, 10 ml of blood was drawn off into a sterile syringe from the femoral vein. The entire collection procedure usually required about 30 min for completion. The blood was then transferred into a clean glass test tube and allowed to stand for 30 min for clotting. The blood was then refrigerated for 24 hr, after which the serum was drawn off and frozen until the time for assay. In order to minimize any adverse affects of the immobilization, samples were only taken every 4 days for a total period of 29 days in order to obtain blood samples at 3-hr intervals over a period of 24 hr. Serum testosterone levels were determined by radioimmunoassay as previously described [van der Walt, et al, 19781. I t should be pointed out that in this assay dihydrotestosterone shows a cross-reactivity of 78%, whereas that of androstenedione is negligible (0.5%). Statistical Analysis Differences between mean values of testosterone at the 3-hr intervals (refer Table I) were examined with a single factor analysis of variance for repeated measures [Winer, Baboon Testosterone Variation 423 TABLE I. Serum Testosterone Concentrations (ngilOaml) at 3-hr Intervals Over 24 hr in Male Papio ursinus Hour of the day Male identification 020P 0500= 0800 1100 1400 1700 200W 2300“ 3 6 14 15 532 2436 1033 952 1443 1405 2845 1686 317 1772 1722 1219 2005 1265 1899 1647 134 604 938 728 710 1178 1609 961 154 1240 738 1192 1675 1868 1302 1336 162 1241 1472 1195 1003 2181 2349 1573 228 750 960 1163 1166 1952 2692 1447 299 977 1443 1666 1359 2998 2541 183i 316 1223 1457 1238 1129 2705 1110 1477 251 655 X k SEM *Sample collected during darkness 19621. This analysis failed to substantiate any differences across sampling periods ( F = 1.82, df = (47),P = .11).Application of an “Fmax” test [Winer, 19621to the data led to the rejection of the hypothesis of homogeneity of variance for the subject males ( F max for data = 5.55; F.,, (df 48,7) = 3.32). The data were therefore subjected to a log” transformation. This procedure eliminated the heterogeneity of variance (F max for data = 1.12; F,9b(df 48,7) = 3.32)but did not affect the evaluation of the hypotheses tested by the analysis of variance. The comparison between the mean testosterone levels during the periods of light and dark was carried out with a t test for paired observations [Snedecor & Cochran, 19671. RESULTS AND DISCUSSION The single factor analysis of variance for repeated measures of the log transformed data substantiated a significant effect of sampling time (f = 2.61, df = (47),P = .03).The mean k SEM of the nontransformed data are plotted in Figure 1. I t is quite clear that in our study the testosterone levels are at their lowest at about 0800 hr in the morning and at their highest at 2000 hr in the evening. During the period of this study the duration of daylight varied between a total of 11 hr, 51 min and 12 hr, 33 min [List, 19711. Sunrise varied between 0641 hr and 0704 hr [Hurley, 19781.This means that the nadir for peripheral testosterone levels in this study occurred approximately 1hr after sunrise. The sunset varied between 1830 hr and 1911 hr [Hurley, 19781. This means that the peak peripheral testosterone levels in this study occurred approximately 1%hr after sunset. The individual means for the periods of light and darkness were examined statistically. The paired t test revealed ahighly significant difference for these two periods (t = 4.84, df = (5),P < .005).The mean k SEM for the light period was 1329 181 ngllOO ml serum in contrast to a level of 1660 f 145 ngilOO ml serum for the dark period. The pattern of peaks and troughs for the baboon is very similar to that which has been reported for rhesus monkeys which were exposed to natural lighting influences [Rose et al, 19781.The pattern is also similar to that which has been reported from other studies of diurnal primates in which animals have been housed indoors and exposed to artificial lighting regimes [Cercopithecus sp., Beattie & Bullock, 1978; Lemur catta, van Horn et al, 1976; Macaca mulutta, Goodman et al, 1974; Michael et al, 19741. The baboon’s pattern is exactly the opposite to that which has been reported for man [Lincoln, et al, 1974; Nieschlag, 1974; Rowe, et al, 19741. The origin of the reversal in pattern between mian and the other diurnal primates thus far studied remains obscure. Our study was con- * Bielert, Howard-Tripp, and van der Walt 424 2400 2100 E 2 -2E 1800 1500 \ rn c 5al 1200 4 Q1 -$ C 900 3 600 v) c“ 300 0 0200h 0500h10800h 1lOOh 1400h 1700h 2000h 2300h 0200h Hour of the Day Fig. 1. Mean concentrations(bounded by k SEM) of serum testosterone over a 24-hrperiodin malePapio rusinus (N = 6). Samples were collected at 3-hr intervals every 4 days. Stippled area, period of natural darkness. ducted during a time of the year when we believe the testosterone levels in our males to be relatively high, as evidenced by a study of the occurrence of seminal emission [Bielert et al, 19801. We believe that a similar diurnal pattern would be revealed at other times of the year, as was shown to be the case for the rhesus [Roseet al, 19781.The question of the importance of light as a “zeitgeber”for the timing of the diurnal changes in testosterone level is an important one, and it is hoped that a study of diurnal testosterone changes in the male baboon may be carried out during a different season of the year some time in the future. CONCLUSIONS 1. The male chacma baboon exhibits a diurnal variation in systemic concentration of testosterone which is very similar to that which has been reported for prosimian and simian primates and is the reverse of that reported for man. 2. With a 3-hr sampling schedule a concentration nadir occurred approximately 1 hr after sunrise at 0800 hr, and the peak mean concentration level occurred approximately 1%hr after sunset at 2000 hr. ACKNOWLEDGMENTS The authors would like to acknowledge the financial support of the University Council of the University of the Witwatersrand to the Primate Behaviour Research Group. The staff of the Central Animal Unit of the University of the Witwatersrand and that of the Steroid Laboratory of the SAIMR are also thanked for their cooperation and assistance. Appreciation is also expressed to Professor J. A. M. Myburgh for permission to employ Baboon Testosterone Variation 425 a number of his adult male baboons in our study. Mr. C. Fullager provided statistical assistance and Mrs. B. Hurwitz is thanked for her conscientious typing. REFERENCES Aso, T.; Goncharov, N.; Cekan, Z.; Diczfalusy, E. Plasma levels of unconjugated steroids in male baboons (Pupio hamadryas) and rhesus monkeys (Macaca mulatta). ACTA ENDOCRINOLOGICA 82644-651,1976. Bartke, A.; Steele, R. E.; Musto, N.; Caldwell, B. V. Fluctuations in plasma testosterone levels in adult male rats and mice. ENDOCRINOLOGY 921223-1228, 1973. Beattie, C. W.; Bullock, B. C. Diurnal variation of serum androgen and estradiol - 17B in the adult male green monkey (Cercopithecussp.). BIOLOGY OF REPRODUCTION 19:36-39, 1978. Bielert, C.; Howard-'hipp, M.E.; van der Walt, L.A. Environmental and social factors influencing seminal emission in chacma baboons (Papio u ~ s ~ ~ uPSYCHONEUROENDOs). CRINOLOGY 5:287-303,1980. Ferin, M.; Carmel, P. W.; Warren, M. P.; Himsworth, R. L.; Frantz, A. G. Phencyclidine sedation as a technique for handling rhesus monkeys effects on LH, GH, and prolaction secretion. P R O C E E D I N G S O F T H E SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE 151:428-433, 1976. Goodman, R. L.: Hotchkiss, J.; Karsch, F. J.; Knobil, E. Diurnal variations in serum testosterone concentrations in adult male rhesus monkeys. BIOLOGY OF REPRODUCTION 11:624-630, 1974. Hurly, R. F. ASTRONOMICAL HANDBOOK FOR SOUTHERN AFRICA, 1979. Cape Town. Astronomical Society of Southern Africa, 1978. Judd, H. L.; Parker, D. C.; Siler, T. M.; Yen, S. S. C. The nocturnal rise of rJlasma testosterone in pubertal boys. JOURhAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM 38:710-713, 1974. Lacerda, L. de; Kowarski, A.; Johanson, A. J.; Athanasiou, R.; Migeon, C. J. Integrated concentration and circadian variation of plasma testosterone in normal men. JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM 37~366-371,1973. Lincoln, G.A.; Rowe, P. H.; Racey, R. A. The circadian rhythm in plasma testosterone concentration in man. pp. 137-149 in CHRONOBIOLOGICAL ASPECTS OF ENDOCRINOLOGY J. Aschoff; F. Ceresa; F. Halberg; eds. Symposia Medica Hoechst 9, Stuttgart, F. K. Schattauer Verlaa 1974. List, R. J . SMITHSONIAN METEOROLOGICAL TABLES. Smithsonian Miscellaneous Collection, 114, 506-507, 1971. Michael, R. P.; Setchell, K. D. R.; Plant, T. M. Diurnal changes in plasma testosterone and studies on plasma corticosteroids in non-anesthetized male rhesus monkeys (Macaca mulatta). JOURNAL OF ENDOCRINOLOGY 63:325-335, 1974. Nieschlag, E. Circadian rhythm of plasma testosterone. pp. 117-128 in CHRONOBIOLOGICAL ASPECTS OF ENDOCRINOLOGY. J. Aschoff; F. Ceresa; F. Halberg, eds. Symposia Medica Hoechst 9, Stuttgart, F. K. Schattauer Verlag, 1974. Perachio, A. A.; Alexander, M.; Marr, L. D.; Collins, D. C. Diurnal variations of serum testosterone levels in intact and gonadectomized male and female rhesus monkeys. STEROIDS 29:21-33, 1977. Resko, J. A.; Eik-Nes, K. B. Diurnal testosterone levels in peripheral plasma of human male subjects. JOURNAL OF CLINICAL ENDOCRINOLOGY 573-576, 1966. Rose, R. M.; Gordon, T. P.; Bernstein, I. S . Diurnal variation in plasma testosterone and cortisol in rhesus monkeys living in social groups. JOURNAL OF ENDOCRINOLOGY 76:67-74, 1978. Rowe, P. H.; Lincoln, G. A.; Racey, P. A.; Lehane, J.; Stephenson, M. J.; Shenton, J. C.; Glover, T. D. Temporal variations of testosterone levels in the peripheral blood plasma of men. JOURNAL OF ENDOCRINOLOGY 61: 63-73, 1974. Sanwal, P. C.; Sundby, A.; Edqvist, L. E. Diurnal variation of peripheral plasma levels of testosterone in bulls measured by a rapid radioirnmunoassay procedure. ACTA VETERINARIA SCANDANAVICA 15:90-99, 1974. Setchell, K. D. R.; Axelson, M.; Simarina, A. I.; Gonischarow, N. P. Urinary steroid excretion and conjugation by the baboon (Pupio hamudryas) - A comprehensive study. JOURNAL OF STEROID BIOCHEMISTRY 809-816, 1976. Snedecor, G. W.; Cochran, W. G. STATISTICAL METHODS. Ames, Iowa, Iowa State University Press, 1967. Steiner, R. A.; Peterson, A. P.; Yu, J. Y L.; Conner, H.; Gilbert, M.; ter Penning, B.; Bremner, W. J. Ultradian luteinizing hormone and testosterone rhythms in the adult male monkey, Macacu fuscicuhris ENDOCRINOLOGY 107: 1489-1493, 1980. van der Walt, L. A.; Wilmsen, E. N.; Jenkins, T. Unusual sex hormone patterns among desert dwelling hunter-gatherers. JOURNAL OF CLINICAL ENDOCRINOLOGY AND METABOLISM 461658-663. 1978.