Changes in endocrine profile and reproductive organs during puberty in the male marmoset monkey (Callithrix jacchus)

Abstract

Data on pubertal maturation in male marmoset, a model for human reproduction, are scant and conflicting. We collected data on novel parameters to characterize puberty. Twenty-five marmoset monkeys were assigned to five age groups by weeks (wk): 21 (pre-pubertal), 43 (onset of puberty), 52 (fully pubertal), 70 (mature), and 116 (fully adult). Serum and intratesticular testosterone and pituitary bioactive chorionic gonadotropin (bioCG) were measured. Testicular development was assessed by ultrasonography, histology, and flow cytometry. Three consecutive blood samples revealed extreme fluctuations in testosterone concentrations, suggesting an erratic secretion. Age-related changes in serum testosterone and pituitary bioCG concentrations were observed. Intratesticular androgens (ITAs) showed high fluctuations within groups at all ages and were high in some animals by 21 wk. Unexpectedly, no correlation between pituitary bioCG and serum testosterone or ITAs was found, but these parameters significantly correlated with testicular weight and volume. These observations were consistent a dependence on the testis growth on bioCG. Unfortunately, the low serum levels of bioCG were not measurable in this study. At 43 wk, the animals reached puberty. At 52 wk of age, animals attained maximum body and epididymal weights and qualitatively normal spermatogenesis, but testes continued growing, reaching a maximum of all parameters at 70 wk of age, without further major changes at the age of 116 wk. It is concluded that (1) gonadal activation is evident at wk 21, (2) the male marmoset reaches the pubertal threshold around 43 wk of age, attains qualitative parameters at 52 wk, matures further to sexual maturity at 70 wk, and (3) serum testosterone and ITAs are highly variable without any identifiable correlation with pituitary bioCG.

Experimental endocrine manipulation by contraceptive regimen in the male marmoset (Callithrix jacchus)

“…While reduced testicular volume was found, the serum testosterone levels remained in the physiological range typical of adult animals (see Chandolia et al (2006)) and the histological evaluation of testicular tissue showed mild effects of reduced spermatogenesis and rarely mixed atrophy. In order to establish the suppressive effects of NETE only and -indirectly -the impact of exogenous testosterone spermatogenesis in Callithrix jacchus -either after initial co-administration with TU or by direct use of NETE only -we added the two treatment groups in which, after TU/NETE administration, NETE only was administered (extended gestagen effect, regimen II) and one group that received NETE only (regimen III).…”

“…ITT and serum testosterone were determined as described by Chandolia et al (1991Chandolia et al ( , 2006. For ITT, frozen testicular tissue samples were homogenized in 250 ml PBS buffer and dissolved by ultrasound.…”

“…The intra-and inter-assay CV were 5.9 and 7.8% respectively and the assay detection limit was 0.68 nmol/l. BioCG of pituitary homogenates was assessed by an in vitro bioassay making use of murine Leydig cells as previously reported (Mü ller et al 2004, Chandolia et al 2006. The intraand inter-assay CV were 8.4 and 20.5% respectively.…”

“…Flow cytometry was performed as described previously , Chandolia et al 2006; briefly, parts of frozen testicular tissue were dissected and thawed in PBS at room temperature. About 10-20 mg tissue were minced for 1 min in staining buffer (PBS (supplemented with 1 mg/ml Both hormones were applied by i.m.…”

Luteinizing hormone receptor splicing variants in bovine Leydig cells

“…At the end of culturing time, medium was collected and measured for testosterone levels using an in-house RIA (Zamecnik et al, 1977;Chandolia et al, 2006), and cells were collected for RNA extraction. Experiments were performed with three independent cultures.…”