The effect of nicotine on central catecholamine neurons and gonadotropin secretion. III. Studies on prepubertal female rats treated with pregnant mare serum gonadotropin
Eneroth, P.; Fuxe, K.; Gustafsson, J.A.; Hökfelt, T.; Löfström, A.; Skett, P.; Agnati, L.
Medical Biology 55(3): 167-176
1977
ISSN/ISBN: 0302-2137 PMID: 895215 Document Number: 111961
The effects of nicotine and its main metabolite cotinine have been evaluated on central catecholamine (CA) levels and turnover and gonadotropin secretion in prepubertal female rats treated with pregnant mare serum (PMS) gonadotropin. The effects on ovulation were also evaluated. PMS was administered on day 30 s.c. resulting in a critical period in the afternoon of day 32. All the pharmacological experiments were performed in relation to the critical period. The serum FSH turnover in the subependymal layer leaving the CA turnover in the external layer unaffected. In the forebrain the only significant change after nicotine treatment was a depletion of DA stores in the tuberculum olfactorium. Studies on intraindividual correlations between serum PRL levels and CA levels in various regions of the brain revealed significant correlation in the subependymal layer in the group treated with nicotine and H44/68 and in the group treated with cotinine and H44/68. Nicotine can reduce and delay LH and PRL secretion via an activation of the lateral and medial tubero-infundibular DA systems, respectively. The actions may be partly mediated over nicotinic acetylcholine receptors, controlling activity in the median eminence DA and NA nerve terminals.