Endocrine Correlates of Sexual Development in the Male Monkey, Macaca fascicularis*

Abstract

To increase our understanding of the physiology of sexual maturation in the primate, we have studied various endocrine correlates of reproductive development in the male monkey, Macaca fascicularis. In a cross-sectional study, we examined 80 monkeys, ranging in age from 2 weeks to more than 8 yr. We weighed, measured testis size, and obtained a single morning blood sample from all animals. Serum LH and testosterone (T) levels were measured by bioassay and RIA, respectively. Based on the criteria of age and testis size, we classified the monkeys into five study groups: neonates, older infants, juveniles, peripubertals, and adults. To characterize hormone secretory patterns and to search for evidence of episodic LH and T secretion during development, we selected animals at random (n > 6) from each study group and bled them at 20-to 30-min intervals during evening hours (between 1900-2300 h). To assess pituitary responsiveness to LHRH during development, we administered LHRH (5 /ig/kg, iv bolus) to groups of neonatal, older infant, juvenile, and adult animals (n > 4). LH and T concentrations were integrated over the 90-min postinfusion period. Analysis of serum LH and T levels measured in single morning blood samples showed significantly higher levels of both LH and T in

Synthesis and Release of Steroids in Intestines from Cynomolgus Monkeys (Macaca fascicularis)

“…Thus, to determine if concentrations of these steroids in the intestine also correlate with age and sex, we measured concentrations of T and 5α-DHT in the feces of 12 immature and mature monkeys of both sexes. Cynomolgus monkeys are immature at 1 to 2 years of age and mature at 10 years of age (Steiner and Bremner, 1981;Meusy-Dessolle and Dang, 1985;Yoshida, 1990). In our study, steroids were detected in the feces of both immature and mature monkeys of both sexes, and their levels were not affected by the age or sex of animal.…”

“…The T concentrations in serum correlate with age and sex (Steiner and Bremner, 1981;Westfahl et al, 1984;Meusy-Dessolle and Dang, 1985;Yoshida, 1990). Thus, to determine if concentrations of these steroids in the intestine also correlate with age and sex, we measured concentrations of T and 5α-DHT in the feces of 12 immature and mature monkeys of both sexes.…”

Body Size, Sperm Competition, and Determinants of Reproductive Success in Male Savanna Baboons

“…Testicular volume has been estimated from linear dimensions by using the formula for a regular ellipsoid (Dixson et al, 1980;Wickings and Nieschlag, 1980;Steiner and Bremner, 1981;Plant, 1985):…”

Perkembangan Fisik Dan Body Image Remaja

“…33 Steiner & Bremner, 1981). Namun, penelitian pada manusia menunjukkan bahwa frekuensi LH pulsa mirip pada anak-anak sebelum pubertas dan dewasa (Penny, Olambiwonnu, & Frasier, 1977;.…”

“…34 Jakacki et al, 1982) 35 . pematangan pubertas sekresi pulsatile gonadotropin dibedakan dengan pola yang sangat berbeda dari rilis LH, dengan ketinggian nokturnal amplitudo pulsa (Boya et al, 1974a;36 Beck & 26 Rowell, T. E. (1977 ;Steiner & Bremner, 1981). Pada manusia, amplifikasi nokturnal ini LH sekresi unik untuk pubertas dan tidak diamati selama masa kanak-kanak atau di orang dewasa yang matang (BOYAR et al, 1972) .Dalam rhesus dan cynomolgus monyet, amplifikasi nokturnal LH sekresi terus sepanjang masa dewasa (Steiner et al, 198038 Tanaman & Zorub, 1982 .Dalam manusia, peningkatan malam di LH sekresi telah terbukti berhubungan dengan tidur 39 , dan mungkin mencerminkan peningkatan tidur terkait di GnRH sekresi.…”