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Restraint Methods of Laboratory Non-Human Primates: A Critical Review

Published online by Cambridge University Press:  11 January 2023

V Reinhardt ,
C Liss  and
C Stevens
V Reinhardt*
Affiliation:
Animal Welfare Institute, PO Box 3650, Washington, DC 20007, USA
C Liss
Affiliation:
Animal Welfare Institute, PO Box 3650, Washington, DC 20007, USA
C Stevens
Affiliation:
Animal Welfare Institute, PO Box 3650, Washington, DC 20007, USA
*
† Contact for correspondence and requests for reprints: 4605 Crescent Road, Madison, WI 5371, USA
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Abstract

Published information provides scientific evidence that traditional, involuntary restraint techniques of research non-human primates are intrinsically a source of distress resulting from fear. It has been documented that common methods of enforced restraint result in significantly increased adrenal activity as well as significant changes in a variety of other physiological parameters. There is no scientific evidence that the animals adequately habituate to involuntary restraint. Numerous reports have been published demonstrating that non-human primates can readily be trained to cooperate rather than resist during common handling procedures such as capture, venipuncture, injection and veterinary examination. Cooperative animals fail to show behavioural and physiological signs of distress. It was concluded that the advantages of training techniques over traditional restraint techniques will have to be explored more extensively in the future for the sake of research subjects and scientific methodology.

Keywords

animal welfarehandlingnon-human primatespsychological well-beingrestraintsocial supportstresstrainingunfamiliar environment
Type
Research Article
Information
Animal Welfare , Volume 4 , Issue 3 , August 1995 , pp. 221 - 238
Copyright
© 1995 Universities Federation for Animal Welfare

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References

Adams, M R, Kaplan, J R, Manuck, S B, Uberseder, B and Larkin, K T 1988 Persistent sympathetic nervous system arousal associated with tethering in cynomolgus macaques. Laboratory Animal Science 38: 279–282Google ScholarPubMed
Anzenberger, G and Gossweiler, H 1993 How to obtain individual urine samples from undisturbed marmoset families. American Journal of Primatology 31: 223–230CrossRefGoogle ScholarPubMed
Arluke, A B 1988 Sacrificial symbolism in animal experimentation: Object or pet? Anthrozoos 2: 98–117CrossRefGoogle Scholar
Berendt, R F and Williams, T D 1971 The effect of restraint and position upon selected respiratory parameters of two species of Macaca. Laboratory Animal Science 21: 502–509Google ScholarPubMed
Bloomsmith, M 1992 Chimpanzee training and behavioral research: A symbiotic relationship. American Association of Zoological Parks and Aquariums (AAZPA)/Canadian Association of Zoological Parks and Aquariums (CAZPA). Annual Conference Proceedings: 403–410Google Scholar
Bouyer, J J, Dedet, L, Debray, O and Rougenl, A 1978 Restraint in primate chair may cause unusual behavior in baboons; Electrocorticographic correlates and corrective effects of diazepam. Electroencephalic Clinical Neurophysiology 44: 562–567CrossRefGoogle ScholarPubMed
Bovard, E W 1959 The effects of social stimuli on response to stress. The Psychological Review 66: 267–277CrossRefGoogle ScholarPubMed
Bunyak, S C, Harvey, N C, Rhine, R J and Wilson, M I 1982 Venipuncture and vaginal swabbing in an enclosure occupied by a mixed-sex group of stump-tailed macaques (Macaca arctoides). American Journal of Primatology 2: 201–204CrossRefGoogle Scholar
Burton, R R, Burns, J W and Smith, A H 1981 Restraint of animals in space research. Physiologist 24 (Supplement 6): S41-S44Google Scholar
Bush, M, Custer, R, Smeller, J and Bush, L M 1977 Physiological measures of non-human primates during physical restraint and chemical immobilization. Journal of the American Veterinary Medicine Association 171: 866–869Google Scholar
Canadian Council on Animal Care (CCAC) 1993 Guide to the Care and Use of Experimental Animals, Volume 1, 2nd edition. CCAC: Ottawa, CanadaGoogle Scholar
Castro, M I, Rose, J, Green, N, Petersen, D and Taub, D 1981 Ketamine-HCl as a suitable anaesthetic for endocrine, metabolic, and cardiovascular studies in Macaca fascicularis. Proceedings of the Society for Experimental Biology and Medicine 168: 389–394CrossRefGoogle ScholarPubMed
Clarke, A S, Mason, W A and Moberg, G P 1988 Interspecific contrasts in responses of macaques to transport cage training. Laboratory Animal Science 38: 305–309Google ScholarPubMed
Clarke, M R, Phillippi, K M, Falkenstein, J A, Moran, E A and Suomi, S J 1990 Training corral-living rhesus monkeys for fecal and blood sample collection. American Journal of Primatology 20: 181 (Abstract)Google Scholar
Coe, C L, Franklin, D, Smith, E R and Levine, S 1982 Hormonal responses accompanying fear and agitation in the squirrel monkey. Physiology and Behavior 29: 1051–1057CrossRefGoogle ScholarPubMed
Coelho, A M, Carey, K D and Shade, RE 1991 Assessing the effects of social environment on blood pressure and heart rates of baboon. American Journal of Primatology 23: 257–267CrossRefGoogle Scholar
Cope, F W and Polis, B D 1959 Increased plasma glutamic-oxalacetic transaminase activty in monkeys due to nonspecific stress effect. Journal of Aviation Medicine 30: 90–94Google Scholar
Cowley, D, Vertein, R, Pape, H and Reinhardt, V 1993 Improving the work environment for animal care personnel of laboratory primates. Animal Technology 44: 129–135Google Scholar
Crockett, C M, Bowers, C L, Sackett, G P and Bowden, D M 1993 Urinary Cortisol responses of longtailed macaques to five cage sizes, tethering, sedation, and room change. American Journal of Primatology 30: 55–74Google ScholarPubMed
Eaton, G G, Kelley, S T, Axthelm, M K, Iliff-Sizemore, S A and Shiigi, S M 1994 Psychological well-being in paired adult female rhesus (Macaca mulatta). American Journal of Primatology 33: 89–99CrossRefGoogle ScholarPubMed
Elvidge, H, Challis, J R G, Robinson, J S, Roper, C and Thorburn, G D 1976 Influence of handling and sedation on plasma Cortisol in rhesus monkeys (Macaca mulatta). Journal of Endocrinology 70: 325–326CrossRefGoogle ScholarPubMed
Epley, S W 1974 Reduction of the behavioral effects of aversive stimulation by the presence of companions. Psychological Bulletin 81: 271–283CrossRefGoogle ScholarPubMed
European Economic Community Council Directive 1986 On the Approximation of Laws, Regulations and Administrative Provisions of the Member States Regarding the Protection of Animals Used for Experimental and Other Scientific Purposes 86/609. Journal Officiel des Communautés Européennes, L 358, December 18Google Scholar
Fielder, F G and Casmer, C J 1966 A device to facilitate the restraint and handling of monkeys with minimal human contact. Laboratory Animal Care 16: 395–402Google ScholarPubMed
Fleischman, A R and Chez, R A 1974 A chair for the chronic study of the pregnant baboon. Journal of Medical Primatology 3: 259–264CrossRefGoogle ScholarPubMed
Fuller, G B, Hobson, W C, Reyes, F I, Winter, J S D and Faiman, C 1984 Influence of restraint and ketamine anaesthesia on adrenal steroids, progesterone, and gonadotrophins in rhesus monkeys. Proceedings of the Society for Experimental Biology and Medicine 175: 487–490CrossRefGoogle ScholarPubMed
Gay, W I 1960 A net designed for capturing caged monkeys. Proceedings of the Animal Care Panel 10: 75–78Google Scholar
Golub, M S and Anderson, J H 1986 Adaptation of pregnant rhesus monkeys to short-term chair restraint. Laboratory Animal Science 36: 507–511Google ScholarPubMed
Goncharov, N P, Taranov, A G, Antonichev, A V, Gorlushkin, V M, Aso, T, Ckan, S Z and Diczfalusy, E 1979 Effects of stress on the profile of plasma steroids in baboons (Papio hamadryas). Acta Endocrinologica 90: 372–384Google ScholarPubMed
Gonzalez, C A, Coe, C L and Levine, S 1982 Cortisol responses under different housing conditions in female squirrel monkeys. Psychoneuroendocrinolgy 7: 209–216CrossRefGoogle ScholarPubMed
Goosen, D J, Davies, J H, Maree, M and Dormehl, I C 1984 The influence of physical and chemical restraint on the physiology of the chacma baboon (Papio ursinus). Journal of Medical Primatology 13: 339–351CrossRefGoogle ScholarPubMed
Gunnar, M R, Gonzales, C A and Levine, S 1980 The role of peers on modifying behavioral distress and pituitary-adrenal response to a novel environment in year-old rhesus monkeys. Physiology and Behavior 25: 795–798CrossRefGoogle ScholarPubMed
Hayashi, K T and Moberg, G P 1987 Influence of acute stress and the adrenal axis on regulation of LH and testosterone in the male rhesus monkey (Macaca mulatta). American Journal of Primatology 12: 263–273CrossRefGoogle ScholarPubMed
Hearn, J P 1977 A device for restraining small monkeys. Laboratory Animals 11: 261–262CrossRefGoogle ScholarPubMed
Heath, M 1989 The training of cynomolgus monkeys and how the human/animal relationship improves with environmental and mental enrichment. Animal Technology 40: 11–22Google Scholar
Hein, P R, Schatorje, J S, Frencken, H J, Segers, M F and Thomas, C M 1989 Serum hormone levels in pregnant cynomolgus monkeys. Journal of Medical Primatology 18: 133–142CrossRefGoogle ScholarPubMed
Hennessy, M B 1984 Presence of companion moderates arousal of monkeys with restricted social experience. Physiology and Behavior 33: 693–698CrossRefGoogle ScholarPubMed
Herndon, J G, Turner, J J, Perachio, A A, Blank, M S and Collins, D C 1984 Endocrine changes induced by venipuncture in rhesus monkeys. Physiology and Behavior 32: 673–676CrossRefGoogle ScholarPubMed
Home Office 1989 Code of Practice for the Housing and Care of Animals Used in Scientific Procedures. HMSO: London, UKGoogle Scholar
Ives, M and Dack, G M 1956 “Alarm reaction” and normal blood picture in Macaca mulatta. Journal of Laboratory Clinical Medicine 47: 723–729Google ScholarPubMed
Kaplan, J R, Adams, M R and Bumsted, P 1983 Heart rate changes associated with tethering of cynomolgus monkeys. Laboratory Animal Science 38: 493 (Abstract)Google Scholar
Kelley, T M and Bramblett, C A 1981 Urine collection from vervet monkeys by instrumental conditioning. American Journal of Primatology 1: 95–97CrossRefGoogle ScholarPubMed
Kiesler, S B 1966 Stress, affiliation and performance. Journal of Experimental Research in Personality 1: 27–235Google Scholar
Kissinger, J T and Landi, M S 1989 The effect of four types of restraint on serum ALT and AST in cynomolgus monkeys. Laboratory Animal Science 39: 496 (Abstract)Google Scholar
Kling, A and Orbach, J 1963 Plasma 17-hydroxycorticosteroid levels in the stump-tailed monkey and two other macaques. Psychological Reports 13: 863–865CrossRefGoogle Scholar
Landi, M S, Kissinger, J T, Campbell, S A, Kenney, C A and Jenkins, E L 1990 The effects of four types of restraint on serum alanine aminotransferase and aspartate aminotransferase in the Macaca fascicularis. Journal of the American College of Toxicology 9: 517–523CrossRefGoogle Scholar
Laule, G 1993 Using training to enhance animal care and welfare. Animal Welfare Information Center Newsletter 4(1): 2,8,9Google Scholar
Lennox, M S and Taylor, R G 1983 A restraint chair for primates. Laboratory Animals 17: 225–226CrossRefGoogle ScholarPubMed
Levison, P K, Fester, C B, Nieman, W H and Findley, J D 1964 A method for training unrestrained primates to receive drug injection. Journal of the Experimental Analysis of Behavior 7: 253–254CrossRefGoogle Scholar
Line, S W, Clarke, A S and Markowitz, H 1987 Plasma Cortisol of female rhesus monkeys in response to acute restraint. Laboratory Primate Newsletter 26(4): 1–4Google Scholar
Line, S W, Markowitz, H, Morgan, K N and Strong, S 1991 Effect of cage size and environmental enrichment on behavioral and physiological responses of rhesus macaques to the stress of daily events. In: Novak, M A and Petto, A J (eds) Through the Looking Glass: Issues of Psychological Weil-Being in Captive and Laboratory Primates pp 160–179. American Psychological Association: Washington, USAGoogle Scholar
Loomis, M R, Henrickson, R V and Anderson, J H 1980 Effects of ketamine hydrochloride on the haemogram of rhesus monkeys (Macaca mulatta). Laboratory Animal Science 30: 851–853Google ScholarPubMed
Luttrell, L, Acker, L, Urben, M and Reinhardt, V 1994 Training a large troop of rhesus macaques to co-operate during catching: analysis of the time investment. Animal Welfare 3: 135–140]CrossRefGoogle Scholar
McNamee, G A, Wannemacher, R W, Dinterman, R E, Rozmiarek, H and Montrey, D 1984 A surgical procedure and tethering system for chronic blood sampling, infusion, and temperature monitoring in caged nonhuman primates. Laboratory Animal Science 34: 303–307Google ScholarPubMed
Manuck, S B, Kaplan, J R, Thomas, B and Clarkson, T B 1983 Behaviorally induced heart rate reactivity and atherosclerosis in cynomolgus monkeys. Psychosomatic Medicine 45: 95–108CrossRefGoogle ScholarPubMed
Mason, J W 1958 Restraining chair for the experimental study of primates. Journal of Applied Physiology 12: 130–133CrossRefGoogle ScholarPubMed
Mason, J W 1972 Corticosteroid response to chair restraint in the monkey. American Journal of Physiology 222: 1291–1294CrossRefGoogle ScholarPubMed
Mason, J W and Mougey, E H 1972 Thyroid (plasma BEI) response to chair restraint in the monkey. Psychosomatic Medicine 34: 441–448CrossRefGoogle ScholarPubMed
Mason, J W, Mougey, E H and Kenion, C C 1973 Urinary epinephrine and norepinephrine responses to chair restraint in the monkey. Physiology and Behavior 10: 801–803CrossRefGoogle ScholarPubMed
Mason, J W, Wool, M S, Wherry, F E, Pennington, L L, Brady, J V and Beer, B 1968 Plasma growth hormone response to avoidance in the monkey. Psychosomatic Medicine 30: 760–773CrossRefGoogle ScholarPubMed
Mason, W A 1960 Socially mediated reduction in emotional responses of young rhesus monkeys. Journal of Abnormal and Social Psychology 60: 100–104CrossRefGoogle ScholarPubMed
Michael, R P, Setchell, K D R and Plant, T M 1974 Diurnal changes in plasma testosterone and studies on plasma corticosteroids in non-anaesthetized male rhesus monkeys (Macaca mulatta). Journal of Endocrinology 63: 325–335CrossRefGoogle ScholarPubMed
Milhaud, C L, Klein, M J and Merkel, M C 1980 A new restraining chair for rhesus monkeys (Macaca mulatta). Journal of Medical Primatology 9: 62–70CrossRefGoogle ScholarPubMed
Mitchell, G and Gomber, J 1976 Moving laboratory rhesus monkeys (Macaca mulatta) to unfamiliar hone-cages. Primates 17: 543–547CrossRefGoogle Scholar
Morrow-Tesch, J L, McGIone, J J and Norman, R L 1993 Consequences of restraint stress on natural killer cell activity, behavior, and hormone levels in rhesus macaques (Macaca mulatta). Psychoneuroendocrinology 18: 383–395CrossRefGoogle ScholarPubMed
Morton, W R, Knitter, G H, Smith, P M, Susor, T G and Schmit, K 1987 Alternatives to chronic restraint of nonhuman primates. Journal of the American Veterinary Medical Association 191: 1282–1286Google ScholarPubMed
Nahon, N S 1968 A device and techniques for the atraumatic handling of the sub-human primate. Laboratory Animal Care 18: 486–487Google ScholarPubMed
Nakamura, R K, Coates, R, Crawford, H and Friedman, D 1982 A flexible restraint chair for the cynomolgus monkey (Macaca fascicularis). Journal of Primatology 11: 178–185CrossRefGoogle ScholarPubMed
National Institutes of Health (NIH) 1985 Guide for the Care and Use of Laboratory Animals. NIH: Bethesda, USAGoogle Scholar
National Institutes of Health (NIH) 1991 Nonhuman Primate Management Plan. Office of Animal Care and Use. NIH: Bethesda, USAGoogle Scholar
Norman, R L, McGIone, J and Smith, C J 1994 Restraint inhibits luteinizing hormone secretion in the follicular phase of the menstrual cycle in rhesus macaques. Biology of Reproduction 50: 16–26CrossRefGoogle ScholarPubMed
Norman, R L and Smith, C J 1992 Restraint inhibits luteinizing hormone and testosterone secretion in intact male rhesus macaques: Effects of concurrent naloxone administration. Neuroendocrinology 55: 405–415CrossRefGoogle ScholarPubMed
Office of Technology Assessment 1986 Alternatives to Animal Use in Research, Testing, and Education. US Government Printing Office: Washington, USAGoogle Scholar
Phillippi-Falkenstein, K and Clarke, M R 1992 Procedure for training corral-living rhesus monkeys for fecal and blood-sample collection. Laboratory Animal Science 42: 83–85Google ScholarPubMed
Phoenix, C H and Chambers, K C 1984 Sexual behavior and serum hormone levels in aging rhesus males: Effects of environmental change. Hormones and Behavior 18: 206–215CrossRefGoogle ScholarPubMed
Prentice, E D, Zucker, I H and Jameton, A 1986 Ethics of animal welfare in research: The institution’s attempt to achieve appropriate social balance. The Physiologist 29: 17, 19, 20Google ScholarPubMed
Priest, G M 1991 Training a diabetic drill (Mandrillus leucophaeus) to accept insulin injections and venipuncture. Laboratory Primate Newsletter 30(1): 1–4Google Scholar
Puri, C P, Puri, V and Anand-Kumar, T C 1981 Serum levels of testosterone, Cortisol, prolactin and bioactive luteinizing hormone in adult male rhesus monkeys following cage-restraint or anaesthetizing with ketamine hydrochloride. Acta Endocrinologica 97: 118–124Google ScholarPubMed
Quadri, S K, Pierson, C and Spies, H P 1978 Effects of centrally acting drugs on serum prolactin levels in rhesus monkeys. Neuroendocrinology 27: 136–147CrossRefGoogle ScholarPubMed
Reinhardt, V 1990 Avoiding undue stress: catching individual animals in groups of rhesus monkeys. Lab Animal 19(6): 52–53Google Scholar
Reinhardt, V 1991 Impact of venipuncture on physiological research conducted in conscious macaques. Journal of Experimental Animal Science 34: 212–217Google ScholarPubMed
Reinhardt, V 1992a Improved handling of experimental rhesus monkeys. In: Davis, H and Balfour, AD (eds) The Inevitable Bond: Examining Scientist-Animal Interactions pp 171–177. Cambridge University Press: Cambridge, UKGoogle Scholar
Reinhardt, V 1992b Transport-cage training of caged rhesus macaques. Animal Technology 43: 57–61Google Scholar
Reinhardt, V 1992c Voluntary progression order in captive rhesus macaques. Zoo Biology 11: 61–66CrossRefGoogle Scholar
Reinhardt, V and Cowley, D 1990 Training stump-tailed monkeys to cooperate during in-homecage treatment. Laboratory Primate Newsletter 29(4): 9–10Google Scholar
Reinhardt, V and Cowley, D 1992 In-homecage blood collection from conscious stump-tailed macaques. Animal Welfare 1: 249–255CrossRefGoogle Scholar
Reinhardt, V, Cowley, D, Eisele, S and Scheffler, J 1991a Avoiding undue Cortisol responses to venipuncture in adult male rhesus macaques. Animal Technology 42: 83–86Google Scholar
Reinhardt, V, Cowley, D, Scheffler, , Vertein, R and Wegner, F 1990 Cortisol response of female rhesus monkeys to venipuncture in home-cage versus venipuncture in restraint apparatus. Journal of Medical Primatology 19: 601–606CrossRefGoogle Scholar
Reinhardt, V, Houser, D, Cowley, D, Eisele, S and Vertein, R 1989 Alternatives to single caging of rhesus monkeys (Macaca mulatta) used in research. Zeitschrift fuer Versuchstierkunde 32: 275–279Google ScholarPubMed
Reinhardt, V, Pape, R and Zweifel, D 1991b Multifunctional cage for macaques housed in pairs or in small groups. American Association for Laboratory Animal Science Bulletin 30(2): 14–15Google Scholar
Rice, J M 1994 Zoo husbandry and research: An integrated approach. Humane Innovations and Alternatives 8: 597–600Google Scholar
Robbins, D O, Zwick, H, Leedy, M and Stearns, G 1986 Acute restraint device for rhesus monkeys. Laboratory Animal Science 36: 68–70Google ScholarPubMed
Rosenblum, I Y and Clouston, F 1981 Normal range and longitudinal blood chemistry and hematology values in juvenile and adult rhesus monkeys (Macaca mulatta). Ecotoxicology and Environmental Safety 5: 401–411CrossRefGoogle Scholar
Sainsbury, A W, Eaton, B D and Cooper, J E 1989 Restraint and anaesthesia of primates. Veterinary Record 125: 640–644Google ScholarPubMed
Scallet, A C, McKay, D, Bailey, J R, Ali, S F, Paule, M G, Slikker, W and Rayford, P L 1989 Meal-induced increase in plasma gastrin immunoreactivity in the rhesus monkey (Macaca mulatta). American Journal of Primatology 18: 315–319CrossRefGoogle ScholarPubMed
Schmidt, E M, Dold, G M and McIntosh, J S 1989 A simple transfer and chairing technique for nonhuman primates. Laboratory Animal Science 39: 258–260Google ScholarPubMed
Schultea, T D and Stein, F J 1981 A simple restraining device for small primates. Lab Animal 10(5): 67–69Google Scholar
Schwindaman, D 1991 The 1985 animal welfare act amendments. In: Novak, MA and Petto, A J (eds) Through the Looking Glass: Issues of Psychological Weil-Being in Captive and Laboratory Primates pp 26–32. American Psychological Association: Washington, USAGoogle Scholar
Smith, E O 1981 Device of capture and restraint of nonhuman primates. Laboratory Animal Science 31: 305–306Google ScholarPubMed
Sullivan, S M and Crary, T L 1991 A new device for restraining nonhuman primates. American Association for Laboratory Animal Science Bulletin 30(2): 18–19Google Scholar
Swan, S M 1970 An apparatus for the transportation and restraint of nonhuman primates. Laboratory Animal Care 20: 1131–1132Google ScholarPubMed
Turkkan, J S 1990 New methodology for measuring blood pressure in awake baboons with use of behavioral training techniques. Journal of Medical Primatology 19: 455–466CrossRefGoogle ScholarPubMed
Turkkan, J S, Ator, N A, Brady, J V and Craven, K A 1989 Beyond chronic catheterization in laboratory primates. In: Segal, E (ed) Housing, Care and Psychological Weil-Being of Captive and Laboratory Primates pp 305–322. Noyes Publications: Park Ridge, USAGoogle Scholar
US Department of Agriculture 1991 Animal welfare, standards, final rule. Federal Register 56: 6499–6500Google Scholar
US Government Principles 1985 Principles for the utilization and care of vertebrate animals used in testing, research, and training. In: Guide for the Care and Use of Laboratory Animals pp 82–83. US Department of Health and Human Services: Washington, USAGoogle Scholar
Vertein, R and Reinhardt, V 1989 Training female rhesus monkeys to cooperate during in-homecage venipuncture. Laboratory Primate Newsletter 28(2): 1–3Google Scholar
Walker, M L, Gordon, T P and Wilson, M E 1982 Reproductive performance in capture-acclimated female rhesus monkeys. Journal of Medical Primatology 11: 291–302CrossRefGoogle ScholarPubMed
Wall, H S, Worthman, C and Else, J G 1985 Effects of ketamine anaesthesia, stress and repeated bleeding on the haematology of vervet monkeys. Laboratory Animals 19: 138–144CrossRefGoogle ScholarPubMed
Welker, C 1993 Ethological research work. On and with primates, and especially the crab-eating monkey, Macaca fascicularis. Journal of the International Association of Zoo Educators 28: 20–31Google Scholar
Wickings E J and Nieschlag 1980 Pituitary response to LRH and TRH stimulation and peripheral steroid hormones in conscious and anaesthetized adult rhesus monkeys (Macaca mulatta). Acta Endocrinologica 93: 287–293Google Scholar