Does IGF-1 Lower HGH Output

[Giants11]

Over time will IGF-1 lower ones natural HGH output?

[Giants11]

Bupmity Bump

[rodge]

are you talking about lr3?

i think that its still not clear wether it does or does'nt supress one's hgh pulses.

-rodge

[Giants11]

I believe it does. However my question becomes, we all know that HGH is not all that anabolic really. So what do you want higher levels of IGF-1 or HGH. My first guess would be IGF-1. Here what Anothony Roberts sent me:

Intravenous administration of recombinant IGF-I lowers serum GHRH and TSH.

Laron Z, Klinger B, Silbergeld A, Lewin R, Erster B, Gil-Ad I.

Institute of Pediatric and Adolescent Endocrinology, Beilinson Medical Centre, Petah Tikva, Israel.

Recombinant IGF-I was administered as an iv bolus of 75 micrograms/kg to 10 patients with Laron type dwarfism (3 children aged 9, 11 and 12 years and 7 adults aged 30.6 +/- 3.5 years) and to 8 healthy subjects (mean age 19.9 +/- 12.1 years) and determinations of IGF-I, GHRH, hGH, TSH, and glucose were made before and at 2, 5, 15, 30, 60, 90, and 120 min. The following effects were observed: a. an immediate, marked and sustained drop in blood glucose (p less than 0.001), more prolonged in the patients; b. in both groups, a dramatic rise in plasma hGH (p less than 0.01) which peaked at 60-90 min; in the patients this occurred after an initial immediate fall in plasma hGH (p less than 0.01); c. a progressive decrease of plasma GHRH and TSH (p less than 0.05, 0.02) in both patients and healthy controls. An hypothesis is put forward that acute and time-limited release of somatostatin by IGF-I is the main cause of the hormonal changes registered. As the IGF-I bolus also suppressed circulating insulin levels, the hypoglycemia is considered to be a direct effect of IGF-I.

[Giants11]

Somatomedin-C mediates growth hormone negative feedback by effects on both the hypothalamus and the pituitary.

Berelowitz M, Szabo M, Frohman LA, Firestone S, Chu L, Hintz RL.

Somatomedin-C [IGF-1]stimulates somatostatin release to a maximum of 390 percent of basal release during short-term (20-minute) incubation of rat hypothalamus. It has no effect on basal or stimulated growth hormone release from primary cultures of rat adenohypophyseal cells during a 4-hour incubation, but inhibits stimulated release by more that 90 percent after 24 hours. These findings suggest that somatomedin-C participates in the growth hormone negative feedback loop with an immediate effect on hypothalamic somatostatin and a delayed effect on the anterior pituitary.

[rodge]

they are talking about huigf-1 and not lr3 igf-1. not sure if it does make a difference tho but could be as real data about it is still rare.

-rodge

[Giants11]

Lr3- Igf-1

[Giants11]

I was under the assumption that LR3 was more potent because of its extended half life but it I would think that it still effects ones negative feedback loop

[rodge]

no matter what the outcome is i always think its a good idea to a couple iu's of hgh when on a lr3 cycle. atleast thats what i do.

-rodge

[Giants11]

no matter what the outcome is i always think its a good idea to a couple iu's of hgh when on a lr3 cycle. atleast thats what i do.

-rodge

Yup it would seem that way.