Influence of formulas with borage oil or borage oil plus fish oil on the arachidonic acid status in premature infants.

Several studies have reported that feeding gamma-linolenic acid (GLA) has resulted in no increase in arachidonic acid (AA) in newborns. This result was ascribed to the eicosapentaenoic acid (EPA)-rich fish oil used in these formulas. Docosahexaenoic acid (DHA) sources with only minor amounts of EPA are now available, thus the addition of GLA to infant formulas might be considered an alternative to AA supplementation. Sixty-six premature infants were randomized to feeding one of four formulas [ST: no GLA, no long-chain polyunsaturated fatty acids; BO: 0.6% GLA (borage oil); BO + FOLOW: 0.6% GLA, 0.3% DHA, 0.06% EPA; BO + FOHIGH: 0.6% GLA, 0.3% DHA, 0.2% EPA] or human milk (HM, nonrandomized) for 4 wk. Anthropometric measures and blood samples were obtained at study entry and after 14 and 28 d. There were no significant differences between groups in anthropometric measures, tocopherol, and retinol status at any of the studied time points. The AA content of plasma phospholipids was similar between groups at study start and decreased significantly until day 28 in all formulafed groups, but not in the breast-fed infants [ST: 6.6 +/- 0.2%, BO: 6.9 +/- 0.3%, BO + FOLOW: 6.9 +/- 0.4%, BO + FOHIGH: 6.7 +/- 0.2%, HM: 8.6 +/- 0.5%, where values are reported as mean +/- standard error; all formulas significantly different (P< 0.05) from HM]. There was no significant influence of GLA or fish oil addition to the diet. GLA had only a very limited effect on AA status which was too small to obtain satisfactory concentrations (concentrations similar to breast-fed babies) under the circumstances tested. The effect of GLA on AA is independent of the EPA and DHA content in the diet within the dose ranges studied.

Modifications of thymulin titers in patients affected with prolonged low or high zinc circulating levels are independent of patients' age.

UNLABELLED: Thymulin (FTS) is a thymic hormone, the bioactivity of which depends on zinc (Zn) incorporation in its molecule (FTS bioactive form: Zn-FTS). Many hormones (T3, GH, PRL, Gn-RH 6-endorphin) and Zn are able to increase thymus trophism and Zn-FTS circulating levels, even in old animals, suggesting that age dependent thymic involution is a reversible phenomenon. FTS circulating levels and thymus trophism are age-dependent. In fact, the decrease of Zn-FTS starts from the age of 10-20 years and proceeds progressively. In 19 uremic patients on hemodialysis (mean age +/- SD: 44.7+/-11.7, range 29-60 years) and 58 patients with prolactinoma (mean age 31+/-7; range 18-58) we found low Zn-FTS levels (expressed as scalar dilution in form of 1/log(2)): 1.5+/-0.5 and 2.1+/-0.7, respectively, vs normal age and sex matched controls: 2.9+/-0.4 and 3.6+/-0.3, respectively; p<0.01. On the contrary, in 41 acromegalic patients (mean age 43+/-12; range 20-63 years) Zn-FTS levels were elevated (4.5+/-0.7 vs controls: 2.8+/-0.3, p<0.01). In all these patients, age-related differences of Zn-FTS circulating levels were lost and Zn-FTS titers were homogeneously low or high according to Zn levels. In fact, in uremic patients and in patients with prolactinoma, Zn levels were low (79+/-26 microg/dl and 82+/-23 microg/dl, respectively, vs control levels: 114+/-12 microg/dl, p<0.01), while They were high in acromegalic patients (141+/-44 microg/dl vs control levels: 112+/-11 microg/dl, p<0.01). After ZnSO(4) administration (400 mg per os/day) for six months. Zn levels increased over the normal range, both in patients with uremia and in patients with prolactinoma (136+/-15 microg/dl and 138+/-18 microg/dl, respectively; p<0.01). Also Zn-FTS levels increased homogeneously independently of age (5.2+/-0.7 and 5.3+/-0.8, respectively); p<0.01, both vs basal and control values; PRL circulating levels did not change. In 20 patients affected with prolactinoma and in 10 acromegalic patients, Zn and Zn-FTS decreased to the normal range, 6, or 12 months after surgical or pharmacological normalization of high PRL and GH circulating levels. In these patients, age-related titers of Zn-FTS were found, such as in controls. IN CONCLUSION: (i) Reduced Zn-FTS levels in patients affected with uremia or prolactinoma and the increased Zn-FTS titers present in acromegalic patients are related to low and high Zn circulating levels, respectively, underlining the importance of Zn in regulating thymulin secretion. (ii) When spontaneous (or induced) hyper- or hypo-zincemia occurs, age-related differences of Zn-FTS titers are lost, suggesting that Zn may overcome the effect of age on thymic function.

Zinc and bromocriptine long-term administration in patients with prolactinomas: effects on prolactin and thymulin circulating levels.

Several studies have demonstrated zinc (Zn), prolactin (PRL) and thymulin (Zn-FTS) interplay: Zn inhibits, in a dose related manner, PRL release from lactotropes in vitro and stimulates thymulin synthesis in vivo both in humans and in animals. PRL receptors are present on thymic epithelial cells (TEC); PRL stimulates TEC trophism and activity. Little is known about the influence of PRL on Zn metabolism, though in prolactinomas we found reduced Zn and thymulin circulating levels. For this reason, we evaluated PRL, Zn, bioactive thymulin (Zn-FTS) and total thymulin (T-FTS: Zn-bound plus Zn-unbound form) serum levels in 58 patients with prolactinomas (PRL: 253 +/- 263 micrograms/L), Zn (82 +/- 23 micrograms/dl), Zn-FTS (2.2 +/- 0.20 log2(-1] and T-FTS (3.7 +/- 0.25 log2(-1] were significantly lower (p less than .01) than those found in age matched controls. Zn-unbound bioinactive thymulin form (FTS) levels were in the normal range. Bromocriptine administration (Brc) (2.5-5 mg p.o., b.i.d. for 9 months) to 20 patients with microprolactinomas lowered serum PRL levels (10.5 +/- 6.2 micrograms/L) and significantly increased (p less than .01) Zn (118.6 +/- 14.7 micrograms/dl), Zn-FTS (3.96 +/- 0.7 log2(-1)) and T-FTS (4.66 +/- 0.7 log2(1)) circulating levels. ZnSO4 administration (400 mg p.o. daily for 3 months) to 6 patients with microprolactinomas, significantly increased (p less than .01) Zn (136 +/- 18 micrograms/dl), Zn-FTS (4.5 +/- 0.5 log2(-1)) and T-FTS (5.6 +/- 0.9 log2(-1)) levels, while caused only a slight decrease in serum PRL concentrations (from 95 +/- 8 to 75 +/- 9 micrograms/L; p: NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Thymic endocrine activity in children with idiopathic growth-hormone deficiency.

Experimental and clinical evidences suggest that thymic endocrine function is modulated by the neuroendocrine network and in particular by growth hormone. The plasma of thymulin has been found reduced in congenital hypopituitarism and increased in acromegalic conditions when compared with the values observed in age-matched controls. In the present paper we have investigated in congenital GH-deficient children the effect of one year therapy with GH on the plasma level of thymulin, IGF-1 and plasma zinc; this last parameter has been checked because zinc is required for thymulin activity and modulates IGF-1 production. The basal thymulin and IGF-1 values are lower in GH deficient children than age-matched controls whereas zinc levels show a slight reduction. GH therapy induces a significant increment both of thymulin and IGF-1 levels and a slight increase of plasma zinc. A positive correlation has been found between zinc values and thymulin activity but not between GH and thymulin. Whether the recovery of thymulin production in GH deficient children by GH therapy is mediated by IGF-1 or by bioavailability of zinc ions remains to be established.