Little is known of the cell biology of Leydig cells during the neonatal activation of the @entity2339 . The current study examined the effect of blockade of the @entity2339 with a @entity1176 antagonist (antide) on the neonatal population of Leydig cells in the new world primate, the @entity7533 . Three sets of twins, age 7 weeks, were studied: in each pair one twin was used as a control, while the other received treatment with @entity1176 antagonist from the day of birth to suppress pituitary gonadotrophin secretion. Leydig cells of treated animals were dramatically different from those of controls. The cells were @entity3202 and exhibited very irregular nuclei. The organelles involved in @entity134 synthesis were reduced to the extent to being barely evident. The smooth endoplasmic reticulum (SER) was greatly diminished in quantity and distribution. The usual form of the SER (anastomosing tubules) was not evident, but, instead, the SER was relatively unbranched. Peroxisomes, organelles involved in transfer of @entity165 to the mitochondria, were greatly reduced in number. Mitochondria were relatively sparse and exhibited a non-typical morphology, as tubular elements of the cristae were rarely evident. Thus, the central apparatus in @entity134 production, the SER, mitochondria and peroxisomes, was essentially shut down in the @entity1176 -antagonist-treated animals. Storage of @entity165 , the precursor of @entity134 biosynthesis, was also not in evidence, as lipid droplets were extremely rare. Two prominent features of control in neonatal marmoset Leydig cells, the membranofibrillar inclusion (MFI) and basal laminae, remain prominent in the Leydig cells of treated animals. Evidence of apoptosis was not observed. These results provide strong support that the gonadotrophic hormones are the primary regulator of neonatal Leydig cell development in primates, and also suggest cell regression, rather than apoptosis, being the mechanism of this inhibition.

Blockade of the hypothalamic-pituitary-testicular axis with a XXXX antagonist in the neonatal marmoset monkey: changes in Leydig cell ultrastructure.

@entity3202 :: ('MESH:D016109', 'Disease') :: ['atrophic'] @entity134 :: ('CHEBI:35341', 'Chemical') :: ['steroid'] @entity2339 :: ('MESH:D007029', 'Disease') :: ['HPT axis', 'hypothalamic-pituitary-testicular (HPT) axis'] @entity1176 :: ('MESH:D007987', 'Chemical') :: ['GnRH'] @entity7533 :: ('9483', 'Species') :: ['common marmoset'] @entity165 :: ('MESH:D002784', 'Chemical') :: ['cholesterol']
@entity1176 :: (MESH:D007987,Chemical) :: ['GnRH']
