title: Effects of sex and age on the growth hormone response to galanin in healthy human subjects.
abstract: The aim of our study was to analyze the effects of sex and age on the GH response to galanin infusion in healthy subjects. We have studied 12 young (age, < 40 yr) nonobese healthy volunteers [6 females: age, 31.0 +/- 2.5 yr; body mass index (BMI), 21.6 +/- 0.9 kg/m2; 6 males: age, 29.2 +/- 1.4 yr; BMI, 23.3 +/- 0.4 kg/m2] and 11 old (age, > 65 yr) healthy subjects (5 females: age, 83.8 +/- 3.8 yr; BMI, 23.4 +/- 1.4 kg/m2; 6 males: age, 79.7 +/- 4.6 yr; BMI, 23.3 +/- 0.2 kg/m2). All subjects received an infusion of synthetic porcine galanin (500 micrograms, iv) in 100 mL saline from 0-45 min. Blood samples for GH measurement were drawn at -15, 0, 15, 30, 45, 60, 90, and 120 min. The GH peaks after galanin treatment in young females (11.9 +/- 2.9 micrograms/L) were significantly (P < 0.05) higher than those in the young males (5.1 +/- 1.8 micrograms/L). Old males showed significantly higher peak GH levels after galanin treatment (8.6 +/- 3.1 micrograms/L) than old females (2.4 +/- 0.6 micrograms/L). The GH peaks and areas under the curve after galanin treatment were significantly (P < 0.05) higher in young than in old females. On the contrary, no significant differences were observed after galanin treatment in young and old males. The magnitude of galanin-induced GH secretion significantly correlated with estradiol levels in young women. Our data seem to suggest that circulating estrogen levels play a crucial permissive role in galanin-induced GH secretion in humans.
authors.affiliation: Cattedra di Clinica Medica and Chimica, University of Brescia, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Giustina
authors.forename: M
authors.initials: M
authors.lastname: Licini
authors.forename: A R
authors.initials: AR
authors.lastname: Bussi
authors.forename: A
authors.initials: A
authors.lastname: Girelli
authors.forename: G
authors.initials: G
authors.lastname: Pizzocolo
authors.forename: M
authors.initials: M
authors.lastname: Schettino
authors.forename: A
authors.initials: A
authors.lastname: Negro-Vilar
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000378:metabolism*; D004958:Estradiol / Q000097:blood; D005260:Female; D019004:Galanin; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D010455:Peptides / Q000494:pharmacology*; D012016:Reference Values; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood
chemical_list: D010455:Peptides; D013739:Testosterone; D004958:Estradiol; D019004:Galanin; D013006:Growth Hormone