Cocaine administration increases the fraction of CART cells in the rat nucleus accumbens that co-immunostain for c-Fos.

In order to further test whether or not psychostimulant drugs activate CART peptide-containing cells in the nucleus accumbens, we examined the fraction of CART positive cells that co-immunostained for c-Fos after administration of saline or cocaine (10 and 25 mg/kg i.p.).

Neurotransmitter transporters synthesis and degradation rates.

The synthesis rate, half-life and degradation rate constant of dopamine and serotonin transporter proteins have been determined using RTI-76, an irreversible inhibitor of ligand binding at transporters, and a model assuming that synthesis rate is zero order and degradation rate is a first order process. The half-lives of transporter recovery after inactivation with RTI-76 are approximately 2-3 days, which are similar to those for other synaptic proteins.

IGF-I but not the IGF-I variant long R(3)IGF-I increases serum IGFBP-3 in adolescent monkeys.

Previous work in rhesus monkeys has shown that both acute or chronic subcutaneous (s.c.) administration of insulin-like growth factor (IGF)-I elevates serum concentrations of IGF binding protein (IGFBP)-3.

Regulation of the growth hormone-insulin-like growth factor I axis in developing and adult monkeys is affected by estradiol replacement and supplementation with insulin-like growth factor I.

Developmental changes in the GH-insulin-like growth factor I (IGF-I) axis were evaluated in female rhesus monkeys to test the hypothesis that estradiol differentially regulates IGF-I secretion and molar ratios of IGF-I to IGF-binding protein-3 (IGFBP-3) from adolescence into adulthood and that estradiol can reestablish GH secretion in the face of enhanced IGF-I negative feedback inhibition of GH. Adult ovariectomized females were compared to ovariectomized adolescent females studied from 18-36 months of age, a period encompassing the juvenile phase through the expected age at first ovulation. A subgroup of adult (n = 5) and adolescent females (n = 5) was treated continuously with human IGF-I (110 micrograms/kg.

Administration of IGF-I affects the GH axis and adolescent growth in normal monkeys.

The present study examined the effects of IGF-I on serum concentrations of IGF binding protein-3 (IGFBP-3) and GH and assessed how treatment with estradiol and IGF-I would stimulate adolescent growth in monkeys with normal pituitary function. In study I, ovariectomized, juvenile female rhesus monkeys (21 months of age; n = 6) received a bolus injection of IGF-I (1 mg/kg s.c.

IGF-I administration advances the decrease in hypersensitivity to oestradiol negative feedback inhibition of serum LH in adolescent female rhesus monkeys.

Developmental increases in serum LH were assessed in female rhesus monkeys to test the hypotheses that (1) the final stages of puberty are characterized by a decrease in hypersensitivity to oestradiol negative feedback of LH and (2) that increases in IGF-I secretion accelerate this decrease in hypersensitivity. In order to test the first hypothesis, serum LH in the absence of oestradiol and in response to three doses of oestradiol were compared between ovariectomized adult (n = 6) and adolescent female monkeys (control group; n = 6). The control females were not treated with oestradiol until serum LH had risen to within the 95% confidence interval of serum LH observed in ovariectomized adults.

Primiparous rhesus monkey mothers are more sensitive to the nursing-induced inhibition of LH and ovarian steroid secretion.

The duration of lactational infertility is prolonged significantly in adolescent, primiparous rhesus monkey (Macaca mulatta) mothers compared with adult, multiparous mothers. The present study examined the hypothesis that this parity/age difference in lactational infertility is due to a difference in the physiological responsiveness to nursing behaviour between adolescent and fully adult mothers and is not a consequence of differences in nursing behaviour, per se. At 22 weeks postpartum, mother-infant pairs were randomly assigned to one of four conditions: primiparous, nursing restricted (PR; n = 9); primiparous, nursing unrestricted (PU; n = 11); multiparous, nursing restricted (MR; n = 12); and multiparous, nursing unrestricted (MU; n = 8).