Effects of active immunization against somatostatin (SRIF) and/or injections of growth hormone-releasing factor (GRF) during gestation on hormonal and metabolic profiles in sows.
Farmer. C C; Dubreuil. P P; Pelletier. G G; Petitclerc. D D; Gaudreau. P P; Brazeau. P P
Key Findings
- GRF‑1‑29 injections (9 mg, three times daily) dramatically increased growth hormone AUC in gestating sows.
- The GH‑boosting effect grew stronger with more days of GRF treatment.
- Immunizing against somatostatin raised antibody levels but did not affect hormone or metabolic outcomes.
- GRF‑1‑29 had no impact on prolactin levels.
Practical Outcomes
- For biohackers, the study confirms that GRF‑1‑29 can raise GH levels, but the data come from pregnant pigs using a very high dose, so direct translation to human dosing is uncertain. The lack of effect from somatostatin vaccination suggests that simply blocking somatostatin may not boost GH in practice. Use GRF‑1‑29 cautiously, focusing on established human dosing protocols rather than the high‑dose regimen used here.
Summary
In pregnant pigs, giving the peptide GRF‑1‑29 (the part of the hormone that tells the body to release growth hormone) three times a day raised the amount of growth hormone in the blood, and the effect got bigger the longer the treatment lasted. Trying to block somatostatin by vaccinating the pigs didn’t change any hormone or metabolic measures.
Abstract
The hormonal responses of gestating sows to immunization against somatostatin conjugated to bovine serum albumin (SRIF-IMM) and/or injections of growth hormone-releasing factor (GRF) were studied with thirty-eight second parity sows. Immunization against bovine serum albumin (BSA-IMM) was used as control. First immunizations were done on day 30 and boosters were given on days 44, 58, 72, 86 and 100 of gestation. Injections of GRF (9 mg of GRF (1-29)NH2 per injection) or saline were given at 0800, 1400 and 2000 hr daily from day 90 of gestation until parturition. Mean body weights of sows at 85 and 110 d of gestation were 196.3 and 210.5 kg, respectively (SE = 0.8). Jugular blood samples were collected from 0740 hr to 1100 hr at 20 min intervals on days 90, 101 and 112 of gestation. On day 112, additional samples were collected from 1340 hr to 1700 hr and from 2140 hr to 2300 hr. At 112 d of gestation, antibody titers against SRIF (% binding, 1:150 dilution) were higher (P less than 0.01) for SRIF-IMM (13.5%) vs BSA-IMM (0.95%) sows. There was no effect of SRIF-IMM nor was there a GRF by SRIF-IMM interaction on any variable measured (P greater than 0.05). Injections of GRF increased (P less than 0.01) the area under the curve (AUC) for growth hormone (GH; 305 vs 1623 ng/min/ml). The increase was greater as days of injection increased (P less than 0.05). Administration of GRF did not affect prolactin (Prl) AUC (P greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Study Information
pubmed
1991
1991-07-01T00:00:00.000Z
10.1016/0739-7240(91)90009-9
15
28