![]() ![]() Practically speaking, successful establishment of captive bred marmosets requires that offspring have experience of rearing their younger siblings before being removed from the family for breeding purposes ( 535, 550, 551). Hence, juveniles and young adults usually have both caregiving and play experiences with their younger siblings. Over the next month carrying time for the infants declines to about 10% with an increase in play and affiliative social interactions of the infants with each other and their older siblings ( 548, 549). In marmoset social groups, composed of parents and older siblings, the infants spend the majority of time during the first 2 weeks being carried by the father (40%) and mother (45%), with the remaining time (15%) accounted for by carrying by older siblings and juveniles ( 548, 549). In new world monkeys, carrying by older siblings of younger siblings enhances survival of subsequent offspring ( 15). Levy, in Knobil and Neill's Physiology of Reproduction (Third Edition), 2006 Primates Our understanding of these simultaneous changes is limited at the present time but further studies in these animals may yield new hypotheses about the ontogeny and molecular evolution of steroid receptors. In addition, multiple other steroid hormone–receptor system changes occurred in the New World primates that are not present in the subjects with Cortisol resistance. In the New World monkeys, evolution and selective pressure seem to have favored the development of a zona fasciculata that can hypersecrete Cortisol without “spilling” steroid precursors with sodium-retaining activity. The mineralocorticoid overproduction in man appears to be due to corticotropin hyperstimulation of the adrenal cortex. In the severe form of the human disease, sodium-retaining corticoids (corticosterone and deoxycorticosterone) are elevated many fold, producing hypertension and hypokalemic alkalosis this does not occur in the New World monkeys. There are significant differences between the human disease and the condition in the New World primates. ![]() Only in the androgen-resistance syndrome (testicular feminization) have qualitative changes in the androgen receptor, such as thermolability and lack of receptor stabilization with sodium molybdate, been described. ![]() For example, vitamin D-dependent rickets type II is associated with reduced nuclear uptake of the vitamin D–receptor complex in skin fibroblasts cultured from affected individuals, and progesterone resistance in the human also has been shown to be associated with a decreased number of receptors. Similarly, the other steroid hormone resistance syndromes described in the human are due to changes in receptor number and not affinity. ![]() Although glucocorticoid resistance of various mutant lymphoma cell lines cultured in vitro has been described, the defect has been shown to be decreased numbers of receptors or defective nuclear translocation. Receptor “modifiers” may be implicated in both situations. The New World monkeys and the patients with the syndrome of Cortisol resistance may represent “affinity mutants” of the glucocorticoid receptor. LIPSETT, in Hormonal Steroids: Proceedings of the Sixth International Congress on Hormonal Steroids, 1983 Synthesis and conclusions ![]()
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