Stimulation of Human-Growth-Hormone Secretion by L-Dopa

Comparison of the Changes in Plasma Human Growth Hormone (HGH) and Immuno-Reactive Glucagon (IRG) after Intravenous and Subcutaneous Injection of Glucagon

“…There are various methods as provocative tests for HGH secretion, including the use of insulin (Roth et al, 1963), arginine (Merimee et al, 1965), glucagon (Mitchell et al, 1969), levodopa (Boyd et al, 1970), ACTH (Zahnd et al, 1969) and metyrapone (Kunita et al, 1970 The mechanism of glucagon stimulated HGH secretion is still unclear. In order to investigate whether the stimulatory effect of glucagon on HGH release may be associated with plasma IRG level itself, plasma IRG levels were measured during glucagon injection in the present experiment.…”

Bromocriptine and Dopamine Receptor Stimulation

“…Levodopa causes an increase in the plasma growth hormone concentration in normal subjects and in most patients with Parkinson's disease (Boyd, Lebovitz & Pfeiffer, 1970). Bromocriptine also causes an increase in growth hormone concentration in Parkinsonian subjects, although this is not invariable and some patients respond to levodopa and not to bromocriptine.…”

Effect of cytidine diphosphate choline on growth hormone secretion in patients with brain or pituitary lesions.

“…have been made concerning the mechanism of regulation of the GH secreting system (Abrams et al, 1966;Boyd et al, 1970;Toivola et al, 1972;Giordano et al, 1973;Martin et al, 1973;Dunn and Arimura, 1974;Mc Intyre and Odell, 1974) but, at least as far as human beings are concerned, many doubts exist, both as to the identification of the nervous structures dealing with the control of the GH release and the specific origin of neurotransmitters with which they relate to the hypophysis.…”

“…Therefore we consider of the following to be fundamental importance:•\the dopaminergic mediation (Boyd et al, 1970), the adrenergic mediation (Blackard and Eidingsfelder, 1968) Our survey was conducted on 42 subjects of both sexes. The group ranged in age from 6 to 70 rears (the average age being 41 years).…”